Debits for service they can not and do not deliver

I had to move to a new home. Telkom could not supply fibre service at the new address and I had to cancel this service - without penalties. That was confirmed by Telkom. Since then I still get a debit on my bill every month for fibre services which I have to pay otherwise they stop my phone service and I am afraid of being put on a black list. I tried everything to stop these debits, but I stopped contacting them because nothing comes from it, and it is a complete waste of time - at least 12 minutes everytime one phones them before any response at all. At this stage they owe me more than R3000 and this amount increases every month. I contacted ICASA, but at this stage they still ignore ICASA completely. I can not recommend Telkom to anyone. Their help service is utterly useless as they do not solve my problem, i.e. if they are not "off-line".