diff --git a/src/DotpayApi/Client.php b/src/DotpayApi/Client.php
index 4c69992..b6466d7 100644
--- a/src/DotpayApi/Client.php
+++ b/src/DotpayApi/Client.php
@@ -4,13 +4,35 @@
 
 use Evilnet\Dotpay\DotpayApi\Contracts\IRequest;
 
+/**
+ * Class Client
+ * @package Evilnet\Dotpay\DotpayApi
+ */
 class Client
 {
+    /**
+     * @var
+     */
     private $username;
+    /**
+     * @var
+     */
     private $password;
+    /**
+     * @var
+     */
     private $base_url;
+    /**
+     * @var \GuzzleHttp\Client
+     */
     private $client;
 
+    /**
+     * Client constructor.
+     * @param $username
+     * @param $password
+     * @param $base_url
+     */
     public function __construct($username, $password, $base_url)
     {
         $this->username = $username;
@@ -19,6 +41,10 @@ public function __construct($username, $password, $base_url)
         $this->client = new \GuzzleHttp\Client();
     }
 
+    /**
+     * @param IRequest $request
+     * @return mixed
+     */
     public function makeRequest(IRequest $request)
     {
         $options = [
diff --git a/src/DotpayApi/Contracts/IRequest.php b/src/DotpayApi/Contracts/IRequest.php
index af45759..4614a8c 100644
--- a/src/DotpayApi/Contracts/IRequest.php
+++ b/src/DotpayApi/Contracts/IRequest.php
@@ -2,9 +2,24 @@
 
 namespace Evilnet\Dotpay\DotpayApi\Contracts;
 
+/**
+ * Interface IRequest
+ * @package Evilnet\Dotpay\DotpayApi\Contracts
+ */
 interface IRequest
 {
+    /**
+     * @return mixed
+     */
     public function toArray();
+
+    /**
+     * @return mixed
+     */
     public function method();
+
+    /**
+     * @return mixed
+     */
     public function path();
 }
diff --git a/src/DotpayApi/DotpayApi.php b/src/DotpayApi/DotpayApi.php
index 8575ca5..a0519d1 100644
--- a/src/DotpayApi/DotpayApi.php
+++ b/src/DotpayApi/DotpayApi.php
@@ -3,14 +3,35 @@
 namespace Evilnet\Dotpay\DotpayApi;
 
 use Evilnet\Dotpay\DotpayApi\Requests\CreatePaymentLink;
+use Evilnet\Dotpay\DotpayApi\Requests\CreateRefund;
 
+/**
+ * Class DotpayApi
+ * @package Evilnet\Dotpay\DotpayApi
+ */
 class DotpayApi
 {
+    /**
+     * @var
+     */
     private $config;
+    /**
+     * @var Client
+     */
     private $client;
+    /**
+     * @var Validator
+     */
     private $validator;
+    /**
+     * @var UrlCreator
+     */
     private $url_creator;
 
+    /**
+     * DotpayApi constructor.
+     * @param $config
+     */
     public function __construct($config)
     {
         $this->config = $config;
@@ -19,11 +40,27 @@ public function __construct($config)
         $this->url_creator = new UrlCreator($this->config['pin']);
     }
 
+    /**
+     * @param $payment
+     * @return mixed|string
+     */
     public function createPayment($payment)
     {
         return $this->getPaymentUrl($this->client->makeRequest(new CreatePaymentLink($this->config['shop_id'], $payment)));
     }
 
+    /**
+     * @param $payment
+     * @return mixed
+     */
+    public function refundPayment($payment){
+        return $this->client->makeRequest(new CreateRefund($this->config['shop_id'], $payment));
+    }
+
+    /**
+     * @param $payment
+     * @return mixed|string
+     */
     public function getPaymentUrl($payment)
     {
         switch ($this->config['api_version']) {
@@ -37,9 +74,13 @@ public function getPaymentUrl($payment)
         }
     }
 
+    /**
+     * @param $data
+     * @return bool
+     */
     public function verifyCallback($data)
     {
         return $this->validator->verify($data);
     }
 
-}
\ No newline at end of file
+}
diff --git a/src/DotpayApi/Requests/AbstractRequest.php b/src/DotpayApi/Requests/AbstractRequest.php
index bbd815e..ba380bd 100644
--- a/src/DotpayApi/Requests/AbstractRequest.php
+++ b/src/DotpayApi/Requests/AbstractRequest.php
@@ -2,17 +2,17 @@
 
 namespace Evilnet\Dotpay\DotpayApi\Requests;
 
+/**
+ * Class AbstractRequest
+ * @package Evilnet\Dotpay\DotpayApi\Requests
+ */
 class AbstractRequest
 {
-    protected $shop_id;
-
-    public function __construct($shop_id)
-    {
-        $this->shop_id = $shop_id;
-    }
-
+    /**
+     * @return array
+     */
     public function toArray()
     {
         return get_object_vars($this);
     }
-}
\ No newline at end of file
+}
diff --git a/src/DotpayApi/Requests/CreatePaymentLink.php b/src/DotpayApi/Requests/CreatePaymentLink.php
index da98476..017cee8 100644
--- a/src/DotpayApi/Requests/CreatePaymentLink.php
+++ b/src/DotpayApi/Requests/CreatePaymentLink.php
@@ -4,36 +4,96 @@
 
 use Evilnet\Dotpay\DotpayApi\Contracts\IRequest;
 
+/**
+ * Class CreatePaymentLink
+ * @package Evilnet\Dotpay\DotpayApi\Requests
+ */
 class CreatePaymentLink extends AbstractRequest implements IRequest
 {
+    /**
+     * @var
+     */
     protected $amount;
+    /**
+     * @var
+     */
     protected $currency;
+    /**
+     * @var
+     */
     protected $description;
+    /**
+     * @var
+     */
     protected $control;
     // protected $language;
+    /**
+     * @var int
+     */
     protected $onlinetransfer = 1;
+    /**
+     * @var int
+     */
     protected $ch_lock = 1;
+    /**
+     * @var int
+     */
     protected $redirection_type = 0;
+    /**
+     * @var string
+     */
     protected $buttontext = 'Return';
+    /**
+     * @var
+     */
     protected $url;
+    /**
+     * @var
+     */
     protected $urlc;
+    /**
+     * @var
+     */
     protected $expiration_datetime;
+    /**
+     * @var array
+     */
     protected $payer = [];
+    /**
+     * @var array
+     */
     protected $recipient = [];
 
+    /**
+     * @var
+     */
+    protected $shop_id;
+
+    /**
+     * CreatePaymentLink constructor.
+     * @param $shop_id
+     * @param $data
+     */
     public function __construct($shop_id, $data)
     {
-        parent::__construct($shop_id);
+        $this->shop_id = $shop_id;
+
         foreach ($data as $key => $value) {
             $this->$key = $value;
         }
     }
 
+    /**
+     * @return string
+     */
     public function method()
     {
         return 'POST';
     }
 
+    /**
+     * @return string
+     */
     public function path()
     {
         return 'api/v1/accounts/'.$this->shop_id.'/payment_links/';
diff --git a/src/DotpayApi/Requests/CreateRefund.php b/src/DotpayApi/Requests/CreateRefund.php
new file mode 100644
index 0000000..23f60b9
--- /dev/null
+++ b/src/DotpayApi/Requests/CreateRefund.php
@@ -0,0 +1,71 @@
+<?php
+
+namespace Evilnet\Dotpay\DotpayApi\Requests;
+
+use Evilnet\Dotpay\DotpayApi\Contracts\IRequest;
+use Evilnet\Dotpay\Exceptions\RequestIntegrityException;
+
+/**
+ * Class CreateRefund
+ * @package Evilnet\Dotpay\DotpayApi\Requests
+ */
+class CreateRefund extends AbstractRequest implements IRequest
+{
+    /**
+     * @var
+     */
+    protected $amount;
+
+    /**
+     * @var
+     */
+    protected $description;
+
+    /**
+     * @var
+     */
+    protected $control;
+
+    /**
+     * @var
+     */
+    protected $operation_number;
+
+    /**
+     * CreateRefund constructor.
+     * @param $operation_number
+     * @param $data
+     * @throws RequestIntegrityException
+     */
+    public function __construct($operation_number, $data)
+    {
+        if(!$operation_number){
+            throw new RequestIntegrityException("Operation number is not set");
+        }
+
+        $this->operation_number = $operation_number;
+
+        foreach ($data as $key => $value) {
+            if(!$value || is_numeric($value) && $value <= 0){
+                throw new RequestIntegrityException();
+            }
+            $this->$key = $value;
+        }
+    }
+
+    /**
+     * @return string
+     */
+    public function method()
+    {
+        return 'POST';
+    }
+
+    /**
+     * @return string
+     */
+    public function path()
+    {
+        return 'api/v3/payments/'.$this->operation_number.'/refund/';
+    }
+}
diff --git a/src/DotpayApi/Response.php b/src/DotpayApi/Response.php
index d7c615d..0dcb7b6 100644
--- a/src/DotpayApi/Response.php
+++ b/src/DotpayApi/Response.php
@@ -2,45 +2,77 @@
 
 namespace Evilnet\Dotpay\DotpayApi;
 
+/**
+ * Class Response
+ * @package Evilnet\Dotpay\DotpayApi
+ */
 class Response
 {
+    /**
+     * @var
+     */
     private $data;
 
+    /**
+     * Response constructor.
+     * @param $data
+     */
     public function __construct($data)
     {
         $this->data = $data;
     }
 
+    /**
+     * @return mixed
+     */
     public function getControl()
     {
         return $this->data['control'];
     }
 
+    /**
+     * @return mixed
+     */
     public function getOperationNumber()
     {
         return $this->data['operation_number'];
     }
 
+    /**
+     * @return mixed
+     */
     public function getEmail()
     {
         return $this->data['email'];
     }
 
+    /**
+     * @return mixed
+     */
     public function getOperationAmount()
     {
         return $this->data['operation_amount'];
     }
 
+    /**
+     * @return mixed
+     */
     public function getOperationCurrency()
     {
         return $this->data['operation_currency'];
     }
-    
+
+    /**
+     * @return mixed
+     */
     public function getOperationDateTime()
     {
         return $this->data['operation_datetime'];
     }
 
+    /**
+     * @return mixed
+     */
     public function getOperationStatus()
     {
         return $this->data['operation_status'];
diff --git a/src/DotpayApi/UrlCreator.php b/src/DotpayApi/UrlCreator.php
index ceebaa6..0524be4 100644
--- a/src/DotpayApi/UrlCreator.php
+++ b/src/DotpayApi/UrlCreator.php
@@ -8,21 +8,36 @@
  */
 class UrlCreator
 {
+    /**
+     * @var
+     */
     private $pin;
 
+    /**
+     * UrlCreator constructor.
+     * @param $pin
+     */
     public function __construct($pin)
     {
         $this->pin = $pin;
     }
 
+    /**
+     * @param $payment
+     * @return mixed
+     */
     public function getPaymentUrl($payment)
     {
         return $payment->payment_url;
     }
 
+    /**
+     * @param $payment
+     * @return string
+     */
     public function getPaymentUrlWithCHK($payment)
     {
         return $payment->payment_url.'&chk='.hash('sha256', ($this->pin.$payment->token));
     }
 
-}
\ No newline at end of file
+}
diff --git a/src/DotpayApi/Validator.php b/src/DotpayApi/Validator.php
index 7679142..0b7e13e 100644
--- a/src/DotpayApi/Validator.php
+++ b/src/DotpayApi/Validator.php
@@ -2,8 +2,15 @@
 
 namespace Evilnet\Dotpay\DotpayApi;
 
+/**
+ * Class Validator
+ * @package Evilnet\Dotpay\DotpayApi
+ */
 class Validator
 {
+    /**
+     * @var array
+     */
     private $keys = [
         'id',
         'operation_number',
@@ -32,13 +39,24 @@ class Validator
         'geoip_country',
     ];
 
+    /**
+     * @var
+     */
     private $pin;
 
+    /**
+     * Validator constructor.
+     * @param $pin
+     */
     public function __construct($pin)
     {
         $this->pin = $pin;
     }
 
+    /**
+     * @param $data
+     * @return bool
+     */
     public function verify($data)
     {
         $concatData = '';
@@ -52,4 +70,4 @@ public function verify($data)
         return $data['signature'] === $hash;
     }
 
-}
\ No newline at end of file
+}
diff --git a/src/DotpayManager.php b/src/DotpayManager.php
index 2331ae3..9614fae 100644
--- a/src/DotpayManager.php
+++ b/src/DotpayManager.php
@@ -6,11 +6,25 @@
 use Dotenv\Exception\InvalidCallbackException;
 use Evilnet\Dotpay\DotpayApi\Response;
 
+/**
+ * Class DotpayManager
+ * @package Evilnet\Dotpay
+ */
 class DotpayManager
 {
+    /**
+     * @var DotpayApi
+     */
     private $dotpayApi;
+    /**
+     * @var
+     */
     private $response;
 
+    /**
+     * DotpayManager constructor.
+     * @param DotpayApi $dotpayApi
+     */
     public function __construct(DotpayApi $dotpayApi)
     {
         $this->dotpayApi = $dotpayApi;
@@ -18,18 +32,38 @@ public function __construct(DotpayApi $dotpayApi)
 
     //It will return url for dotpay transaction
 
+    /**
+     * @param $data
+     * @return mixed|string
+     */
     public function createPayment($data)
     {
         return $this->dotpayApi->createPayment($data);
     }
 
+    /**
+     * @param $data
+     * @return mixed
+     */
+    public function refundPayment($data){
+        return $this->dotpayApi->refundPayment($data);
+    }
+
 
+    /**
+     * @return mixed
+     */
     public function response()
     {
         return $this->response;
     }
 
     //It will listen for dotpay POST with status. We need to calculate hash and check status
+
+    /**
+     * @param array $data
+     * @return Response
+     */
     public function callback(array $data)
     {
         if ($this->dotpayApi->verifyCallback($data)) {
@@ -37,4 +71,4 @@ public function callback(array $data)
         }
         throw new InvalidCallbackException('invalid_hash');
     }
-}
\ No newline at end of file
+}
diff --git a/src/Exceptions/RequestIntegrityException.php b/src/Exceptions/RequestIntegrityException.php
new file mode 100644
index 0000000..2018120
--- /dev/null
+++ b/src/Exceptions/RequestIntegrityException.php
@@ -0,0 +1,12 @@
+<?php
+
+namespace Evilnet\Dotpay\Exceptions;
+
+use Throwable;
+
+class RequestIntegrityException extends \Exception {
+    public function __construct($message = "Value is invalid", $code = 0, Throwable $previous = null)
+    {
+        parent::__construct($message, $code, $previous);
+    }
+}
diff --git a/src/Facades/Dotpay.php b/src/Facades/Dotpay.php
index 70f1ce6..d5c1e1e 100644
--- a/src/Facades/Dotpay.php
+++ b/src/Facades/Dotpay.php
@@ -4,10 +4,17 @@
 
 use Illuminate\Support\Facades\Facade;
 
+/**
+ * Class Dotpay
+ * @package Evilnet\Dotpay\Facades
+ */
 class Dotpay extends Facade
 {
+    /**
+     * @return string
+     */
     protected static function getFacadeAccessor()
     {
         return 'dotpay';
     }
-}
\ No newline at end of file
+}
diff --git a/tests/DotpayRefundTest.php b/tests/DotpayRefundTest.php
new file mode 100644
index 0000000..c6bd2ce
--- /dev/null
+++ b/tests/DotpayRefundTest.php
@@ -0,0 +1,60 @@
+<?php
+
+namespace Evilnet\Dotpay\Tests;
+
+use Evilnet\Dotpay\DotpayApi\Requests\CreateRefund;
+
+use Evilnet\Dotpay\Exceptions\RequestIntegrityException;
+use Tests\TestCase;
+
+/**
+ * Class DotpayRefundTest
+ * @package Evilnet\Dotpay\Tests
+ */
+class DotpayRefundTest extends \PHPUnit\Framework\TestCase
+{
+    /**
+     * @throws
+     */
+    public function test_refund_request_can_be_instantiated()
+    {
+        $request = new CreateRefund('M1006-4674',
+            [
+                "amount"      => 120,
+                "description" => "Refund for payment",
+                "control"     => 123
+            ]
+        );
+        $this->assertTrue(isset($request));
+    }
+
+    /**
+     * @throws
+     */
+    public function test_behavior_when_amount_is_invalid(){
+        $this->expectException(RequestIntegrityException::class);
+        $request = new CreateRefund('M1006-4674',
+            [
+                "amount"      => -1,
+                "description" => "Refund for payment",
+                "control"     => 123
+            ]
+        );
+        $this->assertTrue(isset($request));
+    }
+
+    /**
+     * @throws
+     */
+    public function test_behavior_when_operation_number_is_null(){
+        $this->expectException(RequestIntegrityException::class);
+        $request = new CreateRefund(null,
+            [
+                "amount"      => 120,
+                "description" => "Refund for payment",
+                "control"     => 123
+            ]
+        );
+        $this->assertTrue(isset($request));
+    }
+}