iPhone 3G data roaming

[timbos]

Hello,
I'm in the US right now (I live in the UK) with my iPhone. I just got a text to say that I've used £20 of data since I've been here.
Now: Data Roaming is turned off on my phone (I've checked several times), I've never turned it on. Whenever I've picked the phone up this week to check mail (in Wifi hotspots), I get the warning that data roaming is off, etc etc.
FWIW, I've got the latest version of iOS installed (4.2.1).


So, how has my phone managed to run up this bill for data usage that I'm sure it shouldn't have been able to?

 

[eastercat]

If you're using it as an iPod touch, why not use airplane mode? You can still use wifi.
If I want to keep my phone from using data, I use airplane mode. I haven't personally tried turning off cellular data, but that's also worth a try.

 

[rssfed23]

From what I recall o2 have previously admitted to errors with international data billing and offered some refunds!

I would recommend going into settings then disabling cellular data altogether.

I've just come back from the US (live in UK on O2 also) and did not incur any charges with cellular data completely disabled!

Like the previous poster also said; if you're not using any calling/txting features and relying on mail/voip apps then just enable airplane mode and then re-enable wifi just to be extra sure!