Tariff Increase for Contract

I received an sms yesterday stating as from the 01st of May Vodacom tarriff will increase.<br> <br> One of the reason for taking out a contract was to minimise the billing amount every month by keeping it fixed.<br> <br> No correspondance was received apart from the SMS yesterday. I am in the process of having this contract cancelled and going with another cell company.<br> <br> After being a loyal customer for many years I find this service to be PATHETIC SERVICE FROM VODACOM!!