Stoneleigh Recovery Associates LLC Dont want to lissen to anything I have to say or note any evidence I have Lombard, Illinois

I received a letter out of the blue from this company stating that i owed a medical center $50.26 dating back to April 2002. I was quite shocked as I was living in England at that time and did not emigrate here until Nov 2003. I spoke with a lady called Shan who asked me to provide proof of me being in England . I faxed a copy of my passport including the stamp where I entered this country, I also included a pay slip from my employer in England showing I was working for him in 2002. I thought that this surely would be enough,,But NO, Shan called me back and said that she was not convinced and then transferred me to a male rep who would not give his name.  This person then tried to say that it could be my sons debt and that he used my infomation. I told him NO not possible as my son had passed away. I asked if they could please send me a copy of the said bill I owed so I could check it before sending monie to someone i dont know. I was told no we dont send bills out. If this is the case then how do i know i owe it. I have excellent credit and now am worried that my credit will be damaged, and I am not sure what to do. I am going to wright a cease and desist letter forthwith after I have contacted the medical center in question. The problem is that this company will NOT give me there address, and 411 can not find a listing for them.