Product: Credit card or prepaid card

Ongoing dispute with LordandTaylor.CapitalOne.com Between XX/XX/XXXX and XX/XX/XXXX I paid off my card in full and returned merchandise. I expected a zero balance on my card due to the returns and recalculations of interest charges. One example of interest charges on my XX/XX/XXXX bill was {$11.00} that appears it was not backed out correctly when I returned the merchandise. Over the course of a few months I was charged late fees on what I believe was incorrect interest charges and then interest on top of the late fees. It is really difficult to know from my bills exactly how Capital One calculated interest and I wasn't checking my online statements because I expected a zero balance and possibly even a credit balance. Then in XXXX I noticed in my Mint.com account that I had a balance on my Lord & Taylor Capital One account and started researching the amounts. I called Capital One and was told by an associate the amounts were correct, I escalated to a manager who researched and in XX/XX/XXXX provided finance charge adjustments in the amount of {$26.00} which included correcting the {$11.00} finance charge on my XXXX bill. I also received an interest adjustment of XXXX cents and late fees of {$20.00} were reversed. I appreciated the support in correcting my account, however what I have since learned is Capital One reported me as paying late to the credit bureau ( s  ) which has reduced my credit score by XXXX points in a few months. I am purchasing a car and this incorrect information is impeding my ability to obtain premium rates. I called Capital One again on XX/XX/XXXX and was informed the information they reported was correct and I protested had my statements/fees/interest/finance charges been assessed accurately from XXXX / XXXX to present I don't believe I would have owed any money to Capital One and therefore not have any late payments. Based on the returns the supervisor told me the problem was with Lord and Taylor, not Capital One. I said Lord and Taylor does not service my card, Capital One does and I again communicated I believed Capital One had calculation errors that were not considered or reversed when reporting to the Credit Bureaus. There may have been Reg Z violations but I'm not the expert in how interest and the late fees were calculated and the timing, I was not provided a breakdown, nor did Capital One explain it to me correctly so I am unable to complete further research. 
Capital One supervisors would not provide any remedy other that submit a complaint to the Credit Bureaus and / or write Capital One and it would take 60 - 90 days time for a response. This does not help me as the loan will add upwards of {$120.00} annual interest charges over 5 years ( {$600.00} extra at minimum ) due to the lower credit score. Due to how long it will take Capital One to come to resolution I am the one absorbing the risks and extra costs due to the impacts on my credit reports. No way at this point I will be able to get the premium rate on my auto loan. 

In addition, the last supervisor would not provide any written procedures for me to follow in submitting my complaints, only verbal directions were provided although I requested multiple times for written procedures. 
Truthfully I can't tell at this time exactly how Capital One managed my account and what was provided as a courtesy and what was truly calculating errors on their part and no one at Capital One could provide that information either.