Closing an account: Checking or savings account

I had a banking relationship with Citibank when they decided to close my account with an ending balance of $35000.00 that was never returned to me. They claim they have been trying to verify the check, when nothing needs to be verified because the funds are still there in their banking system a few years since they decided to close my account with my funds in there. Nothing on there end is stating that the funds needs to verified, because the funds are still there with them Citibank! Citibank decided to close my account so they can steal my money!!! They need to return my money like the law requires of them.