The BA.com web portal for booking reward flights using Avios is 100% unusable. Entering any combination of cities sends the status bar spinning for minutes, ultimately resulting in the message ERROR: There was a problem with your request, please try again later.

OK, I'll try your phone line instead. I've now sat on hold for over 35 minutes simply attempting to get a reservationist on the line. This is completely unacceptable. My Avios are functionally worthless if I'm unable to ever use them to actually book a flight. What can I do to get some recompense, because this completely absurd.