Complaint sub-issue: Problem with personal statement of dispute

I have a complaint against XXXX XXXX where I am financing a second car from them. They stopped my statements because they received a returned statement from the post office stating it was undeliverable. This was an error as the address was correct. The following statements explain the events that occurred. I learned I had not received a statement in XXXX months, but I didn't owe anything until XXXX because we stay ahead on all of our bills. On XX/XX/XXXX, I contacted them, and they confirmed that they had the correct address and indicated they had a bill that was sent to the address, which was returned by the post office in error, so they stopped all statements without notifying me. During the call on XX/XX/XXXX, he agreed to remove the late fee and assured me that it would not impact my credit. The late fee was not removed and it was reported as a mark against my credit. This is the first time I've ever had that happen in my life. As I stated, we are always on time. I wrote a letter to complain, and rather than fixing their error, they responded with blatant lies stating that I was not assured it would not impact my credit, I most definitely was. They stated that I signed up for electronic billing XX/XX/XXXX. I did not and have received paper statements since that time, otherwise, why would the representative I spoke with in XXXX have told me that a statement was returned as undeliverable from the P.O with my updated address after the date I supposedly changed to electronic billing ( also at which time my address was different )? In fact, every time I talk to them, they ask if I want to change to electronic billing, and I always decline. They stated I received an email during the three-month period about my bill being due. I did not... In fact, I received an email on XX/XX/XXXX stating that my payment was being processed, and I did not receive another email from XXXX until XX/XX/XXXX stating my payment was scheduled and again on the XXXX stating it was being processed. I have no other emails from XXXX XXXX during the time period in question. I also can not find any texts from them during that time, which was their claim in their response to my written complaint sent in XXXX. In fact, their written response was full of blatant inaccuracies. They indicate that I changed to electronic billing more than a year ago, which I didn't. They say they removed the late fee as they said they would do during our XX/XX/XXXX phone call, which they didn't. That was done in XXXX when I called back ( a call that wasn't mentioned in their letter ) once I learned that the late fee was not removed, and my credit was damaged. They say I wasn't told that they did not promise to remove the late mark from my credit, which they didn't because they promised me that a late mark would not go on my credit to begin with. I don't know whether this is blatant incompetence on their part or lies because they get some type of incentive for reporting people to credit bureaus, but it is nonsense. They messed up all the way around, and I'm being penalized for it. They refuse to remove the mark from my credit despite my exemplary record of payment and the entire issue being their error. Aren't these phone calls recorded by the companies? There should be a way to access a copy of the recording of the phone call on XX/XX/XXXX, on XX/XX/XXXX, and again actually on XX/XX/XXXX. I have attached both my original complaint letter and their response.