over charge on contract

cell c increase their prices during a contract. what is the use of a contract???? i took out a contract with a specific amount of calls i could make to a certain value, with a set amount of data and sms'se... i budget for the same amount and stay within the limits not to have any extra charges to my account, just to find out cell c has the RIGHT to change the prices at any time!!!!!<br> <br> now i either have to pay the new price of pay a cancellation fee on my contract... is this fair???<br> <br> The sales person explained i will pay a set amount for 24 months as long as i stay within the limits.<br> <br> I WILL NEVER TAKE OUT A CELL C CONTRACT AGAIN!!!