<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by brits_in_va:
the woman at the desk did the first 2 tickets then said her pc died and left. 30 mins later!!, she came back with the supervisor,
[ ... ]
The person on the helpdesk at AMEX was useless, she did not understand that the tickets were stolen and she wouldnt get the supervisor.</font>
I was thinking that the initial behaviour was unusually poor for UA, until it registered with me that you said IAD. In that case, it's about the usual (extremely poor) standard I'd expect.
As for Amex, I expect hopeless from them too.
It sounds like Amex's fault, as others have said. Either way, you paid Amex and it's their responsibility to provide non-stolen tickets to you.