iPhone problem at the end of first year

[Luis Ortega]

I bought an iPhone a year ago on pay as you go (in the UK with O2), and the price included the first year free wifi/internet bolt-on.
I used it mostly for the apps on it, the maps gps feature while driving, and reading emails while away from home.
I used the phone very little, so my top ups were only £10 a couple of times during the year.
When the year ended and the bolt on expired, I decided to just use its wifi features at free hotspots or at home, but I noticed that money was being deducted from my balance because the phone or its apps were accessing the internet in some way that was incurring a charge.
I had thought that if I had no wifi bolt-on, the phone would simply not access the internet unless I was at a free wifi hotspot or on my home internet, but apparently it does, and it charges my regular call balance.
Is there any way to prevent the phone or its apps from accessing the internet unless they are on a free wifi? Are the apps that I added at fault or it it the iPhone apps that do this?
Can anyone please suggest some options for someone who uses the iphone very little for calls and texts but likes to use it for maps, apps, email and internet?

 

[WeegieMac]

My understanding is that you need to give O2 notice of your intention to opt out of the bolt on for data once your 12 months expires.

I'm sure in the T&C's it says that on the expiration of your 12 months free data bolt on, you will move onto a paid bolt on automatically unless you opt out.

 

[SnowLeopard2008]

You can turn off 3G and also try airplane mode.

 

[Luis Ortega]

My understanding is that you need to give O2 notice of your intention to opt out of the bolt on for data once your 12 months expires.

I'm sure in the T&C's it says that on the expiration of your 12 months free data bolt on, you will move onto a paid bolt on automatically unless you opt out.

Oh no, that was done, and my wifi bolt on is gone, but the iphone still charges me for accessing the internet on its own.