And obviously, whenever something is in beta or limited rollout, the first step is to remove all traces of the previous (working) system - in this case, SM. Amex, you really screwed up on this one.
And it gets even better - I was looking at reports from other people with the same problem. The CSRs on Amex's website offered to help one person, but could only contact her directly if she tweeted at them (yes, this apparently is real life). This poor old woman had to create a twitter just so she could talk to an Amex rep. Way to stay modern and current at the expense of any kind of customer service, Amex.