addInvoicePayment kills page , kindly help

[CodeQue]

Im new to WHMCS, i developed a merchant payment gateway. The invoice is approved but on the function addInvoicePayment, the page just dies and nothing below is processed.

But if i die the page and display details before the function on my website and then removes the die statement, it works fine and redirect on successful payment. This is really frustrating.

Here is a sample of my code below, is there anything i am doing wrong?

 

logTransaction($gatewayParams['name'], $gateway_response, $transactionStatus);
$paymentSuccess = false;
if ($success) {
    /**
     * Add Invoice Payment.
     *
     * Applies a payment transaction entry to the given invoice ID.
     *
     * @param int $invoiceId         Invoice ID
     * @param string $transactionId  Transaction ID
     * @param float $paymentAmount   Amount paid (defaults to full balance)
     * @param float $paymentFee      Payment fee (optional)
     * @param string $gatewayModule  Gateway module name
     */
    $invoiceId = (int)$invoiceId;
    $paymentAmount = (float)$paymentAmount;
    $paymentFee = (float)$paymentFee;
    addInvoicePayment(
        $invoiceId,
        $transactionId,
        $paymentAmount,
        $paymentFee,
        $gatewayModuleName
    );
    $paymentSuccess = true;
}
/**
 * Redirect to invoice.
 *
 * Performs redirect back to the invoice upon completion of the 3D Secure
 * process displaying the transaction result along with the invoice.
 *
 * @param int $invoiceId        Invoice ID
 * @param bool $paymentSuccess  Payment status
 */
callback3DSecureRedirect($invoiceId, $paymentSuccess);