diff --git a/src/PaymentRequestHelper.php b/src/PaymentRequestHelper.php
index 93329ee..867a7f6 100644
--- a/src/PaymentRequestHelper.php
+++ b/src/PaymentRequestHelper.php
@@ -35,7 +35,7 @@ public static function complement( Payment $payment, AbstractPaymentRequest $req
 		 */
 		$merchant_order_reference = $payment->format_string( $config->get_merchant_order_reference() );
 
-    if ( '' === $merchant_order_reference ) {
+		if ( '' === $merchant_order_reference ) {
 			$merchant_order_reference = $payment->get_id();
 		}