It may just take a while for the AT&T/Apple systems to recognize the update of your account and the activation of your new phone. If it doesn't work tomorrow, then I would make a genius bar appointment. Sorry about the distance between you and your Apple store, but I've never seen a case with this type of error before, so I'd let Apple handle it. You could also try calling and talking with a genius if it's a problem that you can deal with at home. They are usually pretty helpful on the phone if you can get one that doesn't have another appointment at the time.