United Cash Advance Called and accused me of not paying off a loan, would not give me an exact date, and said it was over 400 dollars, Internet

This past week i have been recieving various numbers of phone calls from a group of people saying they work for the government. I finally called them back and they had told me I didnt pay back a loan that I recieved in November.

They kept telling me that we could settle this in a court or out of the books. They then sent me to their accounting office in which you could still hear alot of noise in the background. They then said I needed to pay $445 to settle this agreement. I told them I never recieved anything and if I had then it was already paid off. 

They told me that they would call me in two weeks to collect $200 as part of the payment agreement. They also kept telling me that they were part of the federal government, to be honest it sounded like the same person everytime they transfered me. I dont know what to do in this situation can someone help?