Impossible to cancel contract

I have been struggeling for more than a year now to have my telkom cellphone contract cancelled. I no longer use the service but continue to have debit orders issued against my account. I have tried every channel possible to have the issue settled - at the branches, through e-mails, online chats, social media, etc. but no resolution. I have proof that I paid the settlement and sent all the required documents in time. I am at the end of my witts and will personaly never use the services of Telkom again.