Rejected Transactions from Gateway

[techmalta]

Hello, my gateway returns failed transactions in the form of:

 

osc/checkout_process.php&AcceptReject=F&Message=Merchant does not accept HSBC/Quikcash<BR>Cards Accepted are Visa, Mastercard, Cashlink, Premier, Solo/Switch, Amex (for example)

 

However on checkout process is giving a 404 error - page not found

 

on checkout_process.php I am putting the below code, but not working .... any suggestions?

 

if ($AcceptReject="F") {
tep_redirect(tep_href_link(FILENAME_CHECKOUT_PAYMENT, '', 'SSL'));
 }

 if ($AcceptCancel="Cancel")  {
tep_redirect(tep_href_link(FILENAME_CHECKOUT_PAYMENT, '', 'SSL'));
 }