I'd like to think I'm as clever as this guy.
But I really wish I was this good. Egads!
I will definitely take the first guy's approach:
repeating "Yer not gittin' mah account number," in a Southern drawl.
That and maybe this one:
"jadenton at 01:51 PM *
Personally, I like to keep an air horn next to the phone for this very reason. One good blast and they have to take a time out before calling their next victim."