Ongoing "Telkom" debits to bank account

For the last eight years my company has had a debit to the bank account, saying "Telkom". I have repeatedly tried to have this cancelled, as we do not receive any service for this. All I have is the reference number that is supp****. This appears to be some sort of internet link to this debit, rather than our usual Telkom accounts. I would appreciate help in resolving this, as closing our principal current account is not feasible. Repeated sending of cancellation docs and telephone calls has had no effect. We have had the bank reversing these charges for five months now. Thank you!