AT&T sent my account to collections, yet i have never had AT&T. what can i do about it?

Under the Fair debt Collection Practices Act, you are allowed to dispute the debt within 30 days of the initial written communication from the collection agency (i.e first letter). You have to dispute the debt in writing for the FDCPA to give you any protection. Once the collection agency receives a timely dispute, they must stop all collection activity until they provide you with certain details about the debt. If a collection agency is trying to collect a debt that is not yours, they have to pay statutory damages and any reasonable attorney fees and costs associates with making a claim under the FDCPA (so it shouldn't cost you anything to hire an FDCPA attorney)