Telkom - Billing Errors lead to credit blacklisting

In November 2019 Telkom said they were no longer going to repair the fixed line DSL to my house, and said they would provide an alternative offer. They continued billing for the service (line rental, DSL and Internet service) for another 8 months, and after much 'tooing and froing' passed credits for some of the invoices on some of the months - but leaving an outstanding amount due for charges during this period after they had removed the line.

Now, despite my trying to get them to correct their accounts, they have handed me over to a collecting attorney who will now blacklist me with the credit bureau.

How is it fair that I get a bad credit record through their incompetence? It should reflect against them, not me. Quite aside from all the time I've wasted trying to get them to correct their Invoicing.