Telkom continues to bill after cancellation

I have been trying to cancel my Telkom line since last year. When I phone in they say they only accept emails. I eventually emailed them after whcih I thought the line had been cancelled as I stopped receiving monthly statements, but last month I was informed that the account was not paid since September 2017 and there is a balance of over R2000 on the account. I refuse to pay for something I cancelled and for something I have not been using. Telkom stopped sending me statements, but secretly continued to bill me. My account needs to be removed from Telkom and the outstanding balance needs to be cleared.