I am being repeatedly harrassed by a medical practitioner and their collection agency.

I have an estranged adult son who lives a somewhat transient lifestyle. He owes hospital bills and the hospital has turned me into collections. My son is 26 years old, is not on my insurance and has not lived with me since he was 14 years old. I thought it had been corrected in March of 2019 but it has now started again. The latest bill came today for $2300.000. I have no intention of paying this charge because I am in no way responsible for my son. How can I make this stop, permanently? It has been an ongoing problem throughout the last few years but has gotten worse. Please recommend an attorney here in Charlotte that can put an end to this problem.