Vodacom pricing lies

Upgrade shocker....so Vodacom make me an upgrade offer online which I accept, go through the motions, receive the email from them confirming the value of the upgrade per month (which i still have) so i reckon life is good. Get an SMS from them stating the upgrade, but hey, the amount is different, like 3 times more. so I call them this morning to figure it out and get told that its probably a website pricing issue, but that they have a disclaimer in place to revise pricing as they want so what was displayed and sent to me via email is pretty much worthless. I think I've been with them since the beginning of mobiles .........time to move on to a new provider....