I own a small american owned mom and pop retail business .I use a merchant service and was not happy. In my attempt of changing companies I learned they were they only one my bank said they use.ok. So the bank says we have a customer service rep for them why not talk to him he convinced me to stay with the company and I said I would if I signed no contract and they just started back with my old contract he said he could do that. I said fine.the problem is we agreed to just start back with no new contract business as usual with my old contract . I have since closed my business after 17 years and they want a500$ early termenation fee! I am like are you kidding me they said I signed I new contract furnished the contract to me via email and the signature is not mine they said it is binding to the end of the contract 2 more years with fees Any Advice?

Tell them to sue you, and face charges of falsifying your signature if they do.
Short and sweet!

Since they appear to have no legal proof that you agreed to a new contract, tell them to sue you for the fee.