Is this process server legitimate?

Instead of filing bankruptcy I have been paying off my debts one by one. I have an old payday loan debt that I forgot about until last week when I started receiving phone calls about it. The call was from a blocked number and the woman claimed she was a process server who had some legal paperwork to serve me. She said if I wanted to avoid this I could contact the company who was suing me and pay off my debt. Of course I called the number she gave me and the the lady who answered had very little information about this debt I owe. I remember I did have a payday loan about 3 years ago and it was for $200. I made one payment and then got behind in bills so when the company tried charging my checking account automatically I overdrafted. They kept charging it again and again so I ended up with a whole lot of bank fees plus the amount of the loan. I couldn’t catch up and the bank closed my account. So now this loan company says I will have criminal charges for a bad check unless I pay $1700 immediately.

At first I was really concerned but the more I spoke to the woman, the more I felt like it was all a lie. She became very unprofessional when I asked for details and told me to “stop running my mouth” and “shut up”. I disconnected the call but now every day a “process server” calls me from a blocked number. She just called. I answered and told her I do not want to be contacted anymore because I want to look into the validity of this. She then called 4 more times. I will absolutely pay off the money I owe but I don’t owe $1700. There’s no way! And I don’t want to pay more than I owe just because I was scared into thinking I was being sued.

Is this process server legitimate? I’ve never heard of them calling to tell you before serving you. Doesn’t that defeat the purpose? I actually worked at a payday loan collection agency for a week and I quit because they were doing completely illegal things such as calling and telling people they would have liens placed on their house and car if they didn’t immediately pay. None of it was true. Simply scare tactics. But it worked! People paid! They also used aliases to avoid being in legal trouble. It was awful. I refused to take part in that so I quit. I’m wondering if that’s what this company is doing to me. I have no idea how to go about handling this. I don’t want criminal charges. I would like to pay off the loan amount but the company demanded I pay the $1700 or be sued. I just want to be sure I’m not being scammed here. Is there any way to be sure?