I believe a PFD would be the way to go. If ATT has sold the debt, then they do not have any claim or control of said debt. You will need to deal directly with the CA. I would send them a friendly PFD letter and see what they respond back with.
July 2013 score: EQ FICO 819, TU08 778, EX "806 lender pull 07/26/2013
Goal Score: All Scores 760+, Newest goal 800+
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Current scores after adding $81K in CLs and 2 new cars since July 2013
EQ:809 TU 777 EX 790 Now it's just garden time!
June 2017 update: All scores over 820, just pure gardening now.