I bought a contracted phone in May and returned it within a week. But there's a balance of $600 for the phone stays in my account since then. I called AT&T, went to the local store for many times and at last they told me it's a system delay, which will be solved by November.
Now it's November but the balance is still there, and obviously AT&T has sent debit collectors to ask for the money. Today I called AT&T again, the agent told me it's no longer AT&T's business, I can only talk to the debit collector now. I asked for some proof to show I don't own AT&T money. But he said no because he can't find my information in the system.
I'm now all tired about this stuff, It seems AT&T has made a mistake but don't want to make it right. What should I do?