No recent experience for me but I can heartily sympathise.

I have never had any success with the BA claim form for their own tickets. I seem to recall a persistent error last year where it was rejecting with the message that I have to wait so many days (3 I think) before claiming, 10 days after the flight.

We all put these things down to "BA IT" and "the intern is at it again" but it really is unacceptable. All you can do is phone the gold line, complain, and hope that this fabled 7bn investment actually delivers something functional.