approved benefits than months later revoked them, wants me to pay back $5000

What is the name of your state? New York

I was fired Jun 1st. My company told me I ws laid off. When I filed for Unemployment I was originally approved than denied benefits. The Unemployment office requested info from both my former company and myself. I was given three days to reply which I did. After six weeks had passed, the guy at the unemployment offices called and said he was approving my claim since my former company did not respond. He than released all payments. Two months after that I get a call from the unemployment offices saying that the company finally responded and that the they ruled in the company's favor. THey stopped my checks immediately and want me to pay back the $5000 I have received.

Do I have a right to fight this?

You have the right to appeal the decision; however, no one here can make even a guess at what your chances of success are. There are obviously many, many details missing from your post and without the whole story, it's impossible to judge what chance you have.

What I'm asking is is there specific deadlines companies have to respond to claims, and once the unemployment office approves me and releases all withheld checks can they legally revoke it two months later?

Thanks so much.

Yes, there are specific deadlines employers have to adhere to; however, the UC board has the right to waive those deadlines if the employer provides them with information that leads them to believe that this is the right thing to do in the specific circumstances. Since we have no idea what the circumstances are, there's no way we can judge if this was "right" or not. I would remind you that the UC board is the regulatory agency for UC law; they know what the law is and it is unlikely that they would blatantly disregard it for no reason.

They can legally revoke benefits two months later; in most states they can legally revoke benefits two years later.