Telkom Cancellation impossible - horrific service from call centre

I have been trying to cancel a data contract that I had with Telkom for 13 months now and despite various phone-calls, website 'chats', reference numbers, case numbers, branch visits, it seems to be absolutely impossible to do so. I would warn any person that wants to go into a contract with Telkom to really carefully consider this. Their service is absolutely horrific and it is virtually impossible to get any response from them, in the meanwhile they are just taking money off my account every single month.