mobile network turns on automatically

[mezzmorized]

Hi,
I have a HTC sensation (i'm from oz) and i noticed that today, the mobile network keeps turning itself on. I very rarely use it as i only use my wi-fi at home. It has never done this before. I have to keep turning it off. Have tried checking settings, but nothing i do helps....any ideas. Customer support couldn't help me whatsoever....they were hopeless