I have to agree with mikectza, this is very strange!
I have two cellpone contracts, the iphone is on a business top up 500 at vodacom and after reading this thread i decided to log my airtime usage for a few days, today is day three and my airtime is still exactly where it was, not one cent missing, so i honestly believe that your problem lies somewhere else.
PS: everything is switched off on my phone that uses internet, push notification, mail is on manual, etc.
I'm thinking of buying an iPhone and using it on Pay as You Go. I just want to check, before I buy. Is it possible to configure the phone not to use any data (airtime) without me knowing? ie only allowing apps to "get updates etc" when wireless is available. I don't want to spend $$$ because the phone is updating the weather forecasts every minute.
Thanks