payment.php

См. документацию.

<?if (!defined("B_PROLOG_INCLUDED") || B_PROLOG_INCLUDED !== true) die();
 
$entityId = CSalePaySystemAction::GetParamValue("ORDER_PAYMENT_ID");
list($orderId, $paymentId) = \Bitrix\Sale\PaySystem\Manager::getIdsByPayment($entityId);
 
if ($orderId > 0)
{
    $order = \Bitrix\Sale\Order::load($orderId);
    if ($order)
    {
        $paymentCollection = $order->getPaymentCollection();
        if ($paymentCollection && $paymentId > 0)
        {
            $payment = $paymentCollection->getItemById($paymentId);
            if ($payment)
            {
                $service = \Bitrix\Sale\PaySystem\Manager::getObjectById($payment->getPaymentSystemId());
                if ($service)
                    $service->initiatePay($payment);
            }
        }
    }
}