NRS Recovery from PayDay Loan

Ok I need help. I don't know where to go... I received a payday loan for $500 a few months back... I kept paying the "refinance charge". I had to close my bank account because I got hit with way too many overdraft fees when my account got hit. So I have no recorded of how much money in "refinance charges" I paid through this company but today I got an email from a company called NRS (National Recovery Service) with a balance of $510. They said EPProcessing (The PayDay Loan) turned it over to them. My question is what can I do? I mean I know I've paid well over $400 in charges but I can't prove it since my bank account was closed. HELP! Please!

I live in Texas.