<prompt> Human: In 2014 for a period of 4 months I did a teeth whiting treatment. It was expensive, around 750, but I was getting married in 2015 and it was worth it to me. I paid each of the 3 visits in full before leaving the dentist.Years earlier at a minute clinic, I had an issue because the office told me the services were covered by my insurance, which was a mistake. I got a bill 6 months later for the treatment which I barely remembered having. Ever since then I have never left a doctors appointment, dentist, or anything else without making a full payment for whatever services were performed.So the treatment concluded at the end of 2014 and I leave for another dentist. Fast forward to the middle of 2015 and I received a bill for a past due payment of 239 dollars. I called the office twice and left 2 voicemails. In the second voicemail I said I think the bill is a mistake, if you need any help clearing it up please call me.Fast forward to yesterday. Some of my old mail goes to my parents home and I picked up yesterday. In the bundle was a bill from a different dentist for 239 with a handwritten note saying your immediate attention is required. So I called them this morning and it turns out the dentist changed names and locations. After clarifying that I told them it isnt possible to have a balance, I paid each visit in full before leaving. The woman on the phone said that the whiting wasnt covered by insurance, and I only paid 500 of the 739. I said again, that isnt possible, I paid every visit in full.She told me that I need to prove to her I made the payments and she would apologize and fix my account. I asked her when my last visit was and she couldnt tell me she didnt have that information. She rushed me off the phone and told me she would call me back when she wasnt so busy.I save my old bank statements and was able to dig up the ones from 914,1014, and 1214 which show me making payments of 239, 250, and 239. With proof I called them back and they didnt answer. I called back again and left a voicemail. I called back again and it made the noise like a fax machine. Any other office and I wouldnt have a problem but this office has done this before with not answering the phone. I dont want to get a call from collections saying I owe them money in a few months time. My wife and I are looking to buy a home soon so my credit score cant take a hit because of this foolishness. They are only 30 minutes away. Should I drive to them and speak to them in person? What would happen if they send me to collections? Even though I am in the right could it negatively impact my credit?TL;DR I paid for the dentist in full, 3 separate payments. Dentist doesnt have record of one of the payments and has sent me bills for the services performed in 2014. My bank statements prove I made all the payments. I keep calling them and they wont answer.Edit: thanks for all of your responses! I have off from work tomorrow so I will be going in to the office in person. Edit 2: Thanks for all the advice and feedback. Also thank you for the PMs telling me I couldnt count. I did make a mistake in my initial post, my payments were 250, 250, and 239, those 3 payments along with an 11 bill credit from a previous over-payment totaled the 750 procedure. I drove to the new dentist today and the office was really nice, but it smelled like Burger King. I had no idea why, but it didnt matter to me because I just wanted this done. I brought with me my account statements from September, October, and December of 2014. The woman at the front desk tried to make copies of them and I stopped her. The paperwork had my account number and I wasnt letting her copy that. I had them print out a full account summary of all services and payments during my entire run with the dentist. I then requested a print out of the final bill, totaling 0.00 owed. After she bit into her burger, she printed the bill for me confirming that I now owe them nothing and their system has been updated.So, there are really two victories here. I get to wash my hands of them with proof I owe them nothing, and I found out why a dentist would smell like burgers. Thanks for all your advice!!  <response>: I have been in a similar situation during a home purchase. I had proof and I only had to formally dispute it and show proof of payment to my mortgate lender. Mortgage lenders dont tolerate negative items on your credit history but theyre very open to explanations - especially those with proof.Dont waste your time with these fools. Theyre not compensating you despite it being their mistake. My guess is that their bad recordkeeping finally caused them to audit. It sucks that theyre coming up short and bothering you with their negative assumptions about you. 