Our business just received a call from this same number.  Like Tx Gal, our caller ID read "In Reserve."  The female caller asked to speak with the person that handles our AT&T account.  I told her we were not with AT&T and she hung up on me.

this person called my biz claiming to be from ATT and that we were being over charged and that she would take care of it all.  after totally confusing her....she said she would have to check things out and would call back!!!   this person was a FRAUD.

Wanted to talk to person who handles AT&T account.  Said they wanted to offer discount from what I pay now.  Of course they had no idea what I pay now.  Hung up when I asked too many questions.  Can't reverse call-number gives busy signal