Authorize.net & Website Integration Debugging

Hi, I have a PHP and MySQL based web site integrated with [login to view URL] gateway which was working perfectly fine until few days back. The web project was designed by a programmer who promised to give me free life time support for the project, he even did support the project for a while, but now he is un-traceable. The website is completely database driven and all the client information is logged for every processed/successful and declined orders in my website Webmaster Admin Panel (made by the programmer). Currently the website is not accepting any orders as it's declining all the valid credit cards of my clients, its not logging any "Invoice No." (issued by my website DB), and "Transactions No." (issued by [login to view URL] website and logged by my local DB) in the website's local database, normally when everything use to work fine and a transactions was declined, then the "Invoice No." , "Customers Name" and other Address information was always logged in the local DB and only the "Transactions No." was not logged. But now the "Invoice No.", "Transactions No.", "Customers Name" and other "Address" information is not getting logged at "Webmaster" admin panel (local database driven Order Management System made by the previous programmer for my website) and this information is also not getting logged or getting forwarded to [login to view URL] gateway, becuase when I go to [login to view URL] gateway account (through [login to view URL] website), and check the information log for recently "decline/successful transactions" then no information is getting logged at [login to view URL] admin panel for any recently attempted orders. As far as I can conclude, customers transactions are not getting forwarded to the [login to view URL] gateway and that's why the "Webmaters" admin panel is not logging the customer's information and transaction details either, this can be due to some changes in my webserver local time (made by my hosting company) or any changes made in [login to view URL] gateway's IP address or probably because of something else. This job is for an Expert only who has the ability to understand the coding of an other programmer and who have a alot of experience with [login to view URL] integration. I don't want any (wanna be) or inexperienced programmer to waste his and my time on the project or to ruin the current website code or any previous price less DB records. so bid only if you are 100% confident about fixing it. I have experienced this error in the past too, but luckly then the creator of this project use to fix this error, he use to tell me that this error occurs because my hosting company changes the local web server time on which my website is hosted at, and my application/php code or my webserver’s and [login to view URL] transaction servers local time needs to be same, I can’t say how true is that statement?? But this programmer usually use to take about 5 to 10 mins to fix this error while we both stayed online. This is basically a project job for degugging an existing fully made project and nothing new or additional is required, the programmer just need to find and fix the error that caused the existing project to stop functioning properly.