Aldous and Associates Collection Agency review: I would like for them to take their info off of my credit report.

I had an abhorrent interaction with the supervisor of Aldous and associates collection agency. apparently there is only one supervisor there. He is completely inept. The debt in question was discovered by me getting a notification from my credit report. The agency was saying I owed $100 to my local gym that I am in fact in good standing with. After some digging I realized it was my sons account. He was under age at the time. He added me as a responsible party although the gym made it seem like more of an emergency contact. I did not have to be there to consent to this arrangement which already seems like a red flag. Shouldn't I have to sign something? After seeing the issue I immediate called the collection agency and offered to pay the debt in full right then. I requested they report to the credit bureau that it was a mistake they had reported. It was an obvious mis understanding. I never received one phone call from them. They also claimed they sent a letter which I never saw. I currently use this same gym and would have opened a letter from them had I actually saw it. After requesting that they fix the credit reporting he, the so called supervisor, said, "no we don't do that. when you want to pay you can call later" and he hung up on me. This company is disgusting and should be investigated. Their Facebook page has over a dozen bad reviews and not one good one. I asked Joe for his manager and he (as well as the front desk) says he is the highest position to talk to. With someone as unprofessional as him I find it extremely hard to believe he is the one in charge.