Product: Debt collection

They have hired 'private investigators ; to ask questions about my employment, and my neighbors. 
They use such intimidating tones that my neighbors and coworker felt like I was in some sort of danger. and they were fearful for me. They told them that I owed them a whole lot of money. 
They also stalk ( stake out ) my apartment and whereabouts and follow me home, work and out shopping, and my daily walks. I agreed that they could use a PI to verify and check on the truthfulness of my part ( work and home address ) But these people are stalking me. and my adult children. They have not provided any statements as far as pay off remaining amount. When I leave for work at least 5 vehicles follow. 
In the process of receiving the loan, they had me swear that I would keep in contact with them or they would hire investigators, even when I was in constant communication with them they had people following me. They said that I couldn't join a class action suit. And my loan amount was for a little under XXXX. However she made me sign a paper saying that if I ever defaulted on the loan that I would be charged additional fees such as investigator fees up to XXXX. So I signed to agreements, the one for the proper amount then the other for the XXXX. and a nondisclosure. And she said if it came down to that the latter paper would only be shown in court. And when the company would present the agreements to the investigators she would only show them the latter because no one would want to do checks on someone with that small of a loan amount. 
She also made me sign a paper saying that I don't have XXXX or XXXX  issues, if I have to be investigated. And that they only give these type loans out to a handful of people and her office manager had to be in the room to witness this. And made sure that I wasn't recording the conversation. She also said that if ever questioned about she is obligated and covered by the company to say that " this is a financial institution, they don't do that. ' she also said that the private investigators would only verify where I worked and that it could only be up to 30 days, not necessarily consecutive. And that everything that I have just stated above couldn't be subpoenaed. And I agreed to be 'checked on and verified. ' And I was very stressed out about my money situation because I am a single mom, paying for everything concerning my kids. 
They have paid neighbors and children to stalk me and my family. I have yet to receive any official letter from them or correspondence, about anything about my loan. I asked for my account number never received it. 
I also overheard them deny that they had been following people etc. when I first walked in to the establishment one time. And as we were making the current loan agreement, I said, " so that was actually a thing? '' They have done this to other people, that's why they are so good at hiding their trails of harassment and intimidating. I haven't made a payment in a few months, ( since the last time I was told that I was stalked ) and I still haven't received any letters from the company stating a balance due or anything. Anonymous phone calls have also stopped since I have started logging and video recording the people following me. 
I would also like to add. that I am a law abiding citizen who fell on hard times. I don't even have a speeding ticket. And I have been working at this job for over a year, they did an extensive background check before my hire date. so I know this is not a criminal investigation. As long as they have been following us, they would have had plenty of evidence by now.