Integrated Services Threatening me to take me to court Nationwide

I am getting these phone calls from these people that I never heard of. I ask them the company of the name I they say I had a loan with. Well I call the company and they did not even have a account on me. So the company give me another number they also did not have an account on me. I really do not know if they are trying to get money form people but please watch them. I am going try to figue out how I can report them. Plus I am trying to tell the lady about my situation that I am displaced because of the hurricane she told me she did not care. She said I kids to feed and mortage to pay. This is her job and she is doing it. Plus they are calling my ex mother in law house and harrassing her. These people is craxy. I never took a loan with the company they mention. Watch out for this number 1-855-209-5880