ASSISTANCE IN UPDATING CREDIT REPORT

Good day, I have sent e-mails and made phone calls on numerous occasions in an attempt that Transunion rectify my credit report - which they are quickly to put up all accounts a person is paying off, etc. Once you ask them to update same as most of the accounts are already zero - they are not doing so - why? I don't know. I am in the process of buying a car but to no avail - as they didn't update my credit report. I don't have any Judgments against me, neither am I under debt review - so kindly assist to update my report as I really don't know what to do anymore!