Vodacom not fulfilling contract

I took out a new line with a vodacom retailer and never received the device or sim card so I called the Vodacom customer care line to cancel this contract. I have been trying to cancel the contrct for more than six months. I'm being billed for this contract that I did not receive. I'm calling in at least once a week to find out what is happening but only receive the reply that they are escalating the problem and will contact me in two working days. In the last six months I have not received one call from Vodacom concerning this issue. I would strongly advise against taking out a contract with Vodacom.