Old loan problems

I live in Pennsylvania. I was contacted by a law office from New York stating a payday loan I had taken out with MY CASH NOW over 2 years ago was not paid and now i owe a total of $1500+ dollars. They had my prior banking information and stated that because the ACH authorization i gave them came back as NSF, they were going to be pressing charges against me in my state for writing a "bad check". They had my previous bank information but I had closed out that account due to some possible id theft issues. I had a number of payday loans at the time (broke that habit thank GOD), but I was pretty sure I had paid all of them off. I caled the law office and they sent me a letter of validation stating the amount I currently owe. I called them after I received this letter to ask if they could provide me with the loan douments, and the gentleman/lawyer I spoke to stated it was my responsibility to keep that information and they could not provide me with anything else regarding the loan except their "validation" letter. He offered to let me settle the debt by paying the $1500 dollars but I would not give him my information. I advised I work for a police department and I asked him if it was even legal for them to do this. He stated If I worked for the police I should know the legality of it and it sounded to him that I was just trying to get out of paying a bill. I told him I would not pay something they could not validate. He called me a deadbeat and then went on to say that they will be filing suit and i should lawyer up and then he disconnected the call. My questions are:
1. Can they actually do this? file a criminal charge of a bad check?
2. I have not contacted the loan agency yet but I know i did do business with them in the past. If I find out the debt is valid I will pay it. But would I owe all these accumulated interest fees to over $1500. I cant afford that or even a lawyer to help.
3. What can I do?
Any assistance would be appreciated. Thank you.