Contract Pricing Reverted to old pricing

My contract with Vodacom recently expired and without agreeing to a new one or notifying me of an increase, Vodacom just simply increased my rate for me. When I called them, an agent advised me that my deal expired and that was the reason. As far as I am aware, I should now be on a month to month on the same rate until such time as I decide on another deal with them as has always been the case instead my contract was reverted to the previous package. <br> <br> Maybe it's time to switch providers.<br>