Cancelled service still being billed

During April O ordered VDSL for my house. The technicians were unable to install the service, so I cancelled it through the portal. Telkom sent me an invoice which was debited from my account and I have queried this. I have spoken numerous times to their accounts department and to their support on Facebook, every time receiving assurance that the matter has been resolved. I have since reversed the debit order. Upon receipt of my second invoice I went through the same motions. Still nothing has happened. I have just received my 3rd invoice for a service I don't have. Going to t Telkom store does nothing as the staff keeps telling me I need to phone the call center. Doing that has also done nothing. I have since lodged many tickets, with no resolution.

How difficult is it to cancel a service and remove me from your accounting? The incompetence of Telkom and it's staff is not even a joke.

If you cannot resolve the issue I will consult my lawyer.