diff --git a/src/app/addons/paymentwall/func.php b/src/app/addons/paymentwall/func.php
index 3060305..9b1ca1e 100644
--- a/src/app/addons/paymentwall/func.php
+++ b/src/app/addons/paymentwall/func.php
@@ -78,7 +78,7 @@ function fn_paymentwall_handlePingback($configs)
                 $delivery = new Paymentwall_GenerericApiObject('delivery');
                 $response = $delivery->post(fn_paymentwall_prepare_delivery_confirmation(
                     $orderInfo,
-                    $pingback->getParameter('ref'),
+                    $pingback->getReferenceId(),
                     $paymentInfo['test_mode']
                 ));