Worst Service Ever from TELKOM

I have been trying to cancel a landline number, on behalf on my grandmother, who is a pensioner and cannot afford her landline anymore since the 28th of February 2018. I was asked to fill in cancellation documents and email it to the cancellations department, it was to be resolved within 21 days. Its almost 6months later, and my cancellation form is still at billings deapartment, the bills continue to arrive. I have called telkom every month ( waited minimum of 20min on hold before someone attends to the call) just to be told that they have just forwarded the documents to cancellation department, no reference number can be given, and I cannot be transferred to speak to someone who deals with cancellations. I have spoken to a different consultant every month since than but nothing has happened. It cannot take 6months to cancel a simple landline, telkom is clearly inefficient and ***********. How long can it take for documents from the billings department to reach the cancellations department. Telkom is the worst network I have ever dealt with, would never recommend them to anyone.