Telkom useless and poor service

We are trying since October last year to stop the debit order as we no longer use Telkom as a service provider. It is a total waste of time as Telkom make promises but refuse to cancel the debit order. I see this problem as theft because we no longer use Telkom and we have been trying for months now to stop the debit order but they simply continue deducting more than R 500-00 per month. I snow regard these deductions as ******** and ******* and nothing less than theft.