Cell C not honouring agreement

I've 'upgraded' my contract and was promised that I will keep my free WiFi calling minutes as with my previous contract. I confirmed that 3 times with the agent at Cell C The Grove. That information influenced my decision which contract to take. Cell C didn't honour that agreement and now I'm stuck with an expensive contract that doesn't work for me. The staff at The Grove tells me they can't do anything. There is no accountability at Cell C for information their agents provide. How do I contact the Ombudsman?