The best thing to do if you find the deals are no good is to cancel your account and tell them why.

I realise that a lot of people are trapped on a plan untill vodafone catch up to telecom and let you move prepay<->plan without losing your number, but when they do, call up and change to prepay.

So long as people keep giving them loads of cash they will keep ripping people off like they are. If you think its too expensive then get rid of it. I did and now that I refuse to do any more then $20 every month of topup, its just not that important to me to have money on the phone to waste on overpriced services.