Dairyxox: Apple devices seem to use heaps of data randomly.
I think the default setting on iOS7 is to update all apps automatically?
Turn off all icloud stuff (except maybe find your device) and see if it helps.
This probably isnt what you want to hear, but I had a problem like this & created a thread about it, and after a lot of investigation I believe (not 100% sure) this was the culprit.
Ya it could be. I only have 1 iOS device now which is an iPad but I will try these things too. Again as I said earlier nothing has changed since the last 2 months but its always worth trying everything.