Vodacom, what do I have to do to finally get a contract canceled?

This is the only way to get Vodacom to respond to my cancelation request. I've called 4 times to cancel a contract and everytime I'm told that they will escalate my request and call me back the next day. Needless to say they don't. Interesting that they don't put you through to the customer survey if you're unhappy with the service. Vodacom, what do I have to do to cancel an online upgrade and contract?