Impossible to get Paid up Letter from Telkom

Some tears ago I struggled to cancel a contract I had with Telkom. This resulted in them handing me over and subsequent bad credit record. I subsequently settled the account but cannot for some reasom get a paid up letter from Telkom, resulting in a poor credit rating. They inform me that they cannot find the account to do the letter since the account is paid up. For crying in a bucket, surely a "paid up letter' is a standard template they provide to thousands of ex customers???