<prompt> Human: I called this sleep study center in TX in October 2013 for my sleep study. At this time of making appointment, I was told that my portion will be 120. But when I went there at the night of sleep study actual sleep study time, the person available there told me that my portion is about 550. Then I explained her that I was told that my portion would be 120 and clearly mentioned that I will not be able to pay 550 for study and I want to go back. She then said let her call her supervisor. She then called her supervisor and confirmed me that I will have to pay just 120 and wrote something on the papers which I am not sure what she wrote. Then I paid 120 by credit card.Now after almost 8 months, I got a call from this clinic about this past due. On the phone I explained what exactly happened and I am not responsible for this balance due. I also explained that I paid 120 by credit card and if I had accepted that my portion is 550 I would have paid full amount that day only. Since I paid only 120 it proves what I explained you. Also I explained her that I was asked to come for 2nd sleep study but I did not come because even that 120 my portion I felt high. She said OK to me that time.After a few days I got a statement by mail threatening to send by balance to collection agency. So I called her and explained again. She is she would talk to her supervisor and for now ignore that mail.After a few days I again received same statement by mail threatening to send by balance to collection agency. I called again and that time I am not sure if that was same person to whom I explained already so I explained again. But she said I have to pay or they have to send to collection agency because nothing about what I explained is noted in their system. I refused to pay.I called a couple of days later to check what they have decided and she told me that she has sent this bill to collection agency.Any advice to help this situation would be greatly appreciated I would prefer to solve this without going through too much hassle. What action I could take against the doctors office if it does not go well with collection agency and end up with negative remark on credit score and a lot of time waste stressful time? I just thought about the discussion happened at the time of actual sleep study. I think the person present that time did not have access to their system to add note about this discussion or completely forgot to update the same. But I think she did write something on the papers. I am thinking to call their office again and tell this might have happened and request them to send me the paper to verify what that lady wrote after she confirmed with her supervisor.Thank you  <response>: Ask for all of your records from that office. As in, everything they have no matter what it is. If she wrote it down then you should see it. Dispute the bill in writing, no more phone calls. Phone calls are too hard to prove. 