Fix error model api

Appear error
appear ... affer the pay
Appear blank white page

And the order not appear on my orders


This error on link

http://gazadeal.com/index.php?route=payment/bill_payment/callback&invoice_id=55&is_paid=0


And the order not appear. Remains in lost orders


I want to appear this page When complete the payment
http://gazadeal.com/index.php?route=checkout/success

And when click cancel appear error.. not go to my site


https://crosspayonline.com/bill/api/api.php