I currently have a tab that I bought from AT&T with a 2-year contract but their wireless internet service is terrible, so I'm thinking about canceling it and going back to Frontier DSL. It has a SIM card in it and I used wifi off my DSL before I canceled the DSL. If I now cancel the AT&T, leave the SIM card in (or take it out), can I still use wifi off my Frontier DSL? OR will AT&T disable that when I cancel my contract? I'm trying to determine if my tab will work just on wifi without an internet data plan. Please advise because their intermittent wireless service is horrible and driving me crazy! I know I'm going to have to pay a cancellation fee, but it's too annoying to be in the middle of a transaction online and lose connection.