<prompt> Human: In August of 2015 I had a root canal performed by an Endodontist. The entire procedure cost 1400. I Paid a 300 copay and they bill my insurance for the remaining 1100. My insurance company paid them 1000, claiming that the missing 100 was unauthorized and shouldnt have been charged. My insurance company has the returned check and proof of the 1000 payment. I got a notice in January saying that the Endodontist sent them another 1100 bill for this same service, which my insurance refused to pay understandably. I got a letter from my Endodontist last week claiming that I owe them the entire 1100 and that I have 30 days to pay before they contact a collection agency. I called their office 5 times in the past two weeks in an attempt to speak to someone in billing and work this out, but I always receive an answering service and cannot get in touch with who I need to get in touch with. They say they will call me back but they simply wont do it. I cannot get in touch with anyone at this office to work this out as they wont return my calls.I plan on buying a house in the next few years and I also work in a job that requires a credit check. I cannot have a collection agency contacted because my credit will suffer and a lot of things in my life will go wrong, but I cant get in touch with the endodontist to pay the missing 100. What should I do? Should I contact a lawyer? Would hiring a lawyer likely cost more than paying the endodontist the full 1100, even though they have already been paid 1000? Thanks a lot Reddit.  <response>: Go talk to them in person. 