Telkom won't stop billing me for a cancelled line and is reporting me as a non payer to credit bureaus

In August 2017, I relocated and moved my landline. However the new address has no infrastructure due to cable theft which Telkom refuse to replace. So they cancelled the line.

However they are still billing me every month. Since I pay manually, I have not been paying but need to call to let them know. They eventually reversed the charges in November 2017, only to start billing again in December. Each time I don't pay it, it's reported to the credit bureaus and my score is now damaged with a 190 day "arrears"