Account Paid up, but Telkom has marked my account as defaulted

Was contacted last year by Dept Collectors (Blake and Associates) for Telkom. They told me account was overdue, and was handed to them. And that if I made payment, the account would be closed, and not marked as default.

I made payment immediately after that for the full amount.

I have checked my Credit Report, and Telkom Marked my account as in default (27th May 2022).

This is affecting my credit rating, but I cannot get Telkom or Blake and Associates to remove the Default that they have put on my account. Now if they don't remove this, I will have a mark on my record for 6 years!.

Telkom can contact me for more details.