I played along on a pretty elaborate phone fraud by a person impersonating AT&T. They'd gained access to my account somehow, knew my billing history and info, promised a statement credit and were able to "issue" it—by posting a fraudulent payment from a random checking account. They caused a link to be generated, valid SSL from within att.com, asking for credit card info.
I stopped playing along when they solicited a credit card payment for shipping my, um, free iphones.
It's rough out there!