In Hell with Telkom refusing to acknowledge my request to cancel my landline

I phoned Telkom's call centre a number of times to try and cancel my landline and internet service. I was told, repeatedly, that I could only cancel by sending an email to ***, that there is no department or person they could put me through to cancel the service via a call. I have been emailing my request to cancel since the beginning of November, and yet the service has not been cancelled, Telkom has not acknowledged a single e-mail I have sent, and they keep sending me accounts. What the hell can I do??????