Complaint sub-issue: Their investigation did not fix an error on your report

I have been disputing 2 incorrect credit report items that Citi Bank - Best Buy Credit card filed for me. The issue started when they didn't cancel a " membership '' that they were supposed to cancel for me back in XXXX of XXXX. The renovation of the membership showed up in my XX/XX/XXXX statement and I immediately called Best Buy / Citi and let them know the charge was incorrect since I didn't want to renew the annual membership and they agreed to remove the charge from my card. Because this was not a purchase or a charge I authorized I didn't pay the amount to them. The next month statement still had the charge but now it included late fees and interest. I proceeded to call them again and let them know that this was supposed to be corrected and it never did. They mentioned they will take care of it this month and apologized. For this reason I didn't pay the charges again. The third month the charge still showed up and the only thing they removed was the fees and interest for me. After this third time of calling them again they finally agreed and removed all the charged completely since once again this was not a purchase or a service I agreed on keeping. I thought everything was ok but after my credit was pulled I was made aware that the score dropped drastically due to Citi reporting a 30 and a 60 day non payment for their account. I immediately called Citi / Best Buy to dispute this and the people over the phone ( customer service ) filed the report and agreed with me after explaining this to them. They mentioned this could take up to 30 days to get fixed since they issue reports to the credit bureaus once a month. After the first month I received a letter from Citi / Best Buy saying that after investigation they decided to not remove the late payment reports without giving me a full explanation. I called them a second time thinking this was a mistake and the same thing happened, the person over the phone in customer service agreed with me but once again after 30 days I received a second letter saying they denied my request. At the same time I start disputing this account at XXXX  and they report that Best Buy is denying the claim and is remaining in my report. I finally called a third time and elevate this as much as i could with the biggest rank supervisor available who agrees with my claim ( for the third time ) and explains to me that there is a second filter that evaluates the disputes and come with the final determinations so that was the reason why my 2 previous disputes were denied. During this 3rd dispute the supervisor put a lot more detail on the explanation and promised me they would fix this. This time I received a third letter saying that " the account is no longer in dispute '' and they requested to delete the account in dispute from my credit report. After talking one more time with XXXX  they told me they didnt remove the late payments since the letter just mention to delete the dispute note only. 

This has been extremely frustrating and it has been an issue that is affecting my personal economy and my recently created XXXX. Due to my XXXX I depend on credit lines and loans to keep it on float and for the last 8 months they have been denying personal and XXXX credit lines since they are both tied to my personal credit record that has always been fantastic up to this issue with Citi. 

I really need help from you to get this clarified for good. 

Thanks XXXX XXXX.