Vodacom useless when trying to cancel a contract

For the last 6 months we have been trying to cancel my mother data contract. The most recent call to vodacom was last week where after a struggle with the consultant who keeps on trying to sell you other stuff instead of cancelling the contract like we asked. Finally she advised that the contract was cancelled and that we should receive a cancelation sms within 24 to 48 hours. To date still no sms. Today went to vodacom and they advised the contract is still not cancelled. How useless service provider can you get. Is there any legal steps one can take to just have the contract cancelled because Vodoacom customer service is useless and the personnel at Mall @ Reds vodacom is even worse.