Mondeo Mobile / Vodacom

I was phoned by a lady in February and she told me that she was from Vodacom, but in fact that was a lie. I was told that she wants to add data and airtime onto my existing contract and it won't cost me an extra cent. I agreed but when I went to Vodacom in April to upgrade I was told that I am only due in 2 years time. I was never informed that this is a new 2 year contract. I was given a Vodacom call centre number to phone but when I phoned I was told that I had in fact upgraded my contract with Mondeo Mobile. I had never even heard of them and I go to Vodacom every second year myself to upgrade my contract. I have made numerous calls to Mondeo Mobile with no help at all. Shocking service. They told me that I upgraded and can't cancel the contract unless I pay R3600. They won't send me a copy of the taped conversation and tell me that they are not in the wrong. I was told that they will however send the taped conversation to a Vodacom shop, but when I went to Vodacom they told me that they have nothing to do with contracts taken out via the phone. So no help. At the end of the day it is still a Vodacom contract so I can't see how they can not be interested at all to help. What do I do? One thing is for sure, I have lost all confidence in Vodacom and their add ons.