Emergency- So-called attorney calls

Hello I had a PDL which was illegal HydraFund III I sent out my letter, closed my acct and said I would pay back principal $100, I know its not alot but I have had some financial hardship recently. I never heard from them after letter but got a call today from some dude stating he was a marshal and that Im being sued in my county and need to call back the number and gave me a case #. I called the lady said I was being charged with 3-10 b's and yadda yadda yadda, bank fraud, check fraud but I can pay $290 right now over the phone. I told her the loan was illegal and she said no it's not they are gonna send someone to my house with paperwork and serve me, but she never asked me my new address which I wouldn't have given to her anyway. So I called my county courthouse and they said there is nothing with the name or ss #. The company said their name was Alliance Solutions in Charlotte, NC which does not exist when I googled it. Is there anything to be worried about or what should I do? Thank you so much.