Immediate help troubleshooting HotSpot Payment issues

I have a freeradius server that I use for my hotspot system, custom front end and back end. Nothing has changed on my server in days, and the payment portion was working a day ago, now today no-one can transition from my site to the paypal/[login to view URL] site to actually make a payment. I need someone to help me troubleshoot this and resolve this issue. You must be familiar with linux, payment gateways, freeradius, or just very good at linux and php and can figure anything out! This is an immediate need, not 2 days, not 3 days, this is a RIGHT now project. If you bid, be prepared to start working immediately.