I try to answer questions on the att internet support forums. In the last two days there have been
three posts of a similar scam. Oddly, I just answered one just before I came here and saw this thread.
The poster said they were being asked for $871. Wonder where they came up with that number. The other two were, if I recall, around $900. This latest poster didn't go in to any details but I did reply to ask for the details.
I'm only mentioning this here just to inform that this scam is not limited to fastmail email addresses.