Poor service yet again

Poor service yet again from Vodacom. I called through to the call center four times to cancel my contract and convert to prepaid. I was told that I will receive an sms and till date, I have not received anything. What do I have to do to have my request processed? I had an issue with Vodacom when I initially took out my contract and having an issue now when I am trying to cancel. I would never recommend Vodacom to anyone and would never take up any services with them again.