Vodacom are underhanded *****s

I wanted to upgrade my account. After going instore twice and asking if I was dew for a upgrade I decided to upgrade online for the new iPhone 6S. I was phoned on the Monday by the consultant which took me through the process. I asked the consultant repeatedly if I was only going to pay 899 from now on. The consultant confirmed this every time. After receiving the new unit I went instore to purchase a screen protector where I asked the consultant to just make sure. I was then informed there is still an additional 200 a month till February as I prematurely upgraded, which was never communicated. I phoned the Internet Upgrade centre back to complain the manager said he would sort it out. The consultant that made the mistake and admitted fault phoned me back and said the will credit me the money. I asked for this in writing and received nothing. Vodacom said that there consultant could not give me the krediet as he wasn't authorised. But I asked repeatedly to speak to the superiors of the consultant as was refused as he informed me he was told to sort out the situation. I am forced to be bul**** and cancel my contract although Vodacoms representative admits fault on recording.