Order details missing -- using HSBC payment gateway

Hi I hope I am posting on the correct forum. I need some help. We have been using zen cart for a year. Yesterday, there was an order that has shown on our bank report but was not in the admin. I did not receive an email either. I have received orders correctly since then - no problems. All the order numbers are sequential. I have no idea what the customer has orderedbut I have recievd the payment! I had to contact them to explain as luckily the customer details were saved. This has happened only once before and I put to to the fact that I had not cleaned the log activity when we first launched. We are using HSBC integrated by third party

Could this be a bug or a sign of a hacker? (pardon my ignorancce) what should I do- I would be grateful for any suggestions..
Jay
https://www.iwfurniture.com

Hi jay soma,
I have read about people having the same kind of problems with other payment modules and it normally seems to be customers exiting/closing the window without completing the payment gatway service and being returned to your site.