credit report and paid up letter

good day, i would to complain about this guys, when they need their money they will call you now and then and they dont take time to put you in itc, no i have paid them in full, but on my credit report is still showing the account is in arrears and i paid them before my credit report was updated, i have to even call them to close my account, 2 people said they will send me my paid up letter even now im still waiting and my credit report still low because of them