Lender want to talk to my attorney ?

If you told your lender you have an attorney, it would be normal for them to ask to speak with him or her, as that is their job.

It sounds like you got banned for stealing, which you admitted you. If you were fined, you may have gone through Court or as Mr. Rafter asked, you...

How should I proceed with my case?

As you have an attorney, follow their advice as they know your case better than anyone online.e

I moved your case to Child Custody so that an attorney in that area can best answer you.

Someone signed my name as a cosigner.

I am sorry, but you didn't ask a question.

I agree with the prior answer. You only file a proof of claim if they owe you money.

The prior attorneys are correct and you need to work this out before it affects their SSI. That is very nice of you.

SSA sent a letter saying that I was overpaid for a month and I will receive $700 around October and on the first of each month !

I agree with Mr. Pont that the question is unclear. The way I read it, which could be wrong, is that you come into money and you told SSA that you...

You need to talk to your attorney, or get a bankruptcy attorney immediately to get this corrected.

Can I file for bankruptcy and leave the US?

As Mr. Wolfe said, you need to talk to a local bankruptcy attorney about your situation, but most student loans will survive bankruptcy.