Dissatisfied client

I was handed over to this company i have been paying them every month when it was my last payment i called requesting a paid up letter which i was told it would be sent to me and they never did i had to call again and only then i was told that they couldn't see some of my payments and they needed a statement to verify and it was their fault because they were upgrading their system no one said anything to me i sent my statement and they gave me the paid up letter however on credit bureau I'm still showing as someone who is in arrears with them where as now i have paid in full...i just want them to remove my name from the bureau what they are doing is wrong