Current Balance R0.00 but Listed on the Credit bureau. No one can tell me why or assist.

Since my last review on 17 July, I have tried to get some feedback from Telkom, but to no success. In the mean time I have received a SMS stating I have been blacklisted due to none payment, I have phone Telkom(081180) and they have confirmed that I owe them nothing. Now I am phoning every 3 days trying to get the letter from them stating that I don't owe them, but nothing is being done. I am told they will escalate the case, no one is willing to get back to you, you just have to have faith that this time someone will send the letter.

How is it possible that they don't inform you of billing discrepancies or even follow the correct procedure for blacklisting someone (even though I have paid all my bills and I am not even a client anymore) but they don't seem to care that they have made a mistake and it could cause them more damages?

If anybody knows if I have a legal right here and how I could go about getting this resolved, please let me know.