********* contract price increase

I received a mail from Vodacom that my contract will increase on 1 May. I upgraded my contract on 1 Jan, which means that I'll have to pay an unexpected R20pm more for the next 20 months!I'm sure Vodacom will say it's in their small print/Ts&Cs, but ironically no one ever made me aware of this small print when I took out the contract.Why not increase your NEW contracts and give consumers the choice to rather go to MTN or CellC?Does this mean I should be glad that my contract increased by \only"R20"