Vodacom lying to customers

Months ago an agent called me on behalf of Vodacom offering me a contract renewal which would end up significantly reducing my contract fee. I agreed to the terms and conditions only to find out afterwards that the person had incorrectly informed me and that I would still be charged just as much. I have called in to complain about this and the agents I spoke to all have agreed that I was misinformed, actually **** to. They promised to follow up and call back and get a manager to call me, nothing has happened. I was told to go to the store which I did at Kenilworth center only for them to tell me that I need to request the recording be sent to the store. This was 2 weeks ago and still nothing. What should I do to get actual service from Vodacom?