Impossible standards for contract cancellation

I am trying to get my mobile data service with Telkom cancelled. Like my previous experience they make it hard as possible, so you spend months to sort it out. No way Telkom! I wan't my contract completely cancelled by 31 December 2017.

If I log in with self service, there is a "Cancel Service" option. Now I go through this futile exercise of proceeding with that option, and then when completing the final steps, I get an unhelpful that the request cannot be completed and giving my mobile number as the reference (really?) When I phone customer care, they snottily inform me that the cancellation cannot be done telephonically, jumping the gun, because I wanted to enquire why the online self service doesn't work. The agent seemed blissfully unaware that was an option they had on the self service section.

I don't want to send million of emails and speak to hundreds of people to get this cancellation DEMAND, not REQUEST, finalised. So Telkom sort out your ****py technology and your abysmal customer care, and allow me to complete my cancellation without bureaucratic nonsense.