Commission Junction API Script

This is a 2nd attempt at this project...Please, ONLY BID on this if you're familiar with CJ's API. We have a CPA site and reward our users for completing offers, we're currently only using MaxBounty and want to add CJ. Since we pay commission on the successful completion this script needs to 100% verify that the user has completed the task before we credit their account...and also needs to be 100% verified that it's a 'response' coming from CJ, not someone trying to spoof the system - we hate paying out money we don't have ;) We already have the databases, and the membership software in place, you will not need to create ANYTHING other than this one 'page/script' that will verify if the user has completed the CPA action. We are currently looking for a programmer on a full-time basis, our work has expanded rapidly and our current programmer cannot keep up...we've been posting small jobs like these to hopefully find the right match for what we do, so bid with that in mind. Thanks for looking, happy bidding.