Messing up my credit report with account that's paid off.

I pai up my account in May and had it closed but they kept on adding arrears that are still on my credut record to date and affect my rating negatively. I had to call multiple times and sent from one person to another to have the account finally closed but still have to deal with the incorrect arrears on my record. Very quick to update arrears but more than 5 months now clearing those arrears on my records is not a priority to them. This is highly frustrating and a major inconvenience on my end financially.