BILLED MONTHS AFTER CANCELLING SERVICE

I cancelled an ADSL service in November 2017. It was not on contract etc. I am still being billed after numerous visits to Telkom stores and countless calls to help lines. Every time I go in or call everyone tells me they can see that the service was cancelled and they will sort it out, yet months later I am still being billed. I have stopped the debit order from my account, which incurs bank chargers, and now unbelievably I am being penalized for non payment of an account that I do not have nor for a service I cancelled half a year ago.