Vodacom not dealing in good faith

My contract became due for upgrade, but I was unsure of which phone I wanted, I asked them to put the contract on pay as you go. They phoned me back and said I could upgrade my sim only and then do a full upgrade at any time when I decided on a phone. I went into a store to upgrade, but they refused me and said I am only due for upgrade in about 2 years. I phoned the vodacom cancellations department and was told they would listen to my recording and come back to me on Saturday. I am still waiting.