Price Increase on a Contract Price

I have received an email from Vodacom that states that both of my contracts pricing will be increasing even though I have a contract for two years.<br> <br> I contacted the call centre and was told that I could lay a complaint on the line as there is no facility to do that. I was told that there is a clause in the contract that allows for increases. I think that is a lot of hogwash and should not be allowed.<br> <br> This needs to be rectified.