Error in Scheduling PA Exam

I have been attempting to schedule my next exam (PA) this week, and keep running into an error when I get to the Prometric website:

I have been calling NCARB for the past 4 days. Each time, they have promised a call back and resolution to the issue, but so far I have received neither. I find it frustrating that, following the purchase of a $235 seat credit, I have spent hours of my personal and work time attempting to solve a technical issue that exists between NCARB and its testing agency. 

Has anyone else experienced this? Any insight would be greatly appreciated.

Thank you!