PA Payday Loan Help.

Back in February I applied for and received a payday loan from Kenwood Services LLC. Days after the initial deposit was made ($200), a second deposit was made ($200), from an SSM Group. I admit to verifying information and approving the first loan, but I never spoke with anyone from SSM Group. I didn't notice that this second deposit was made, as I had received a deposit from my employer on the same day. By the time I caught it, I had already spent some of the money. At this point, my greatest concern was that another company had somehow gotten ahold of my account info. I told Kenwood Services that I was closing the account, and that I would make payments as soon as I received a written guarantee that the account would be closed once a certain amount was paid. They refused to send me anything in writing. They then started calling me as "The Lombardo, Davis, and Goldman" lawfirm. At this point, they began threatening me with legal proceedings. Leaving messages from unlisted numbers with no way for me to return the call. They claimed to have a "docket number" which is an impossibility unless they had already filed charges. When I asked about this they said that this was an in house number. I told them I would see them in court. I had asked repeatedly for something in writing, and they refused. I said I would not pay without company information and a guarantee that they would no longer harass me. They said they would take this as a refusal to pay.
I want to pay the principal back, but I do not want to make the situation worse. THey are now contacting me as a another company, also threatening prosecution. I just want to know what is plausible and what is not. I pay my bills, but I will not pay if they will just carry on with the threats and collection efforts. I also have sent e-mails asking them to cease and desist. They have not recognized receipt of these, though I sent them read-receipt requested. I don't know how to proceed. At this point, I almost want to go to court. I have documented everything, and short of recording phone calls, I have all our correspondence. How can I put an end to to this?