Hi
Whilst I can understand the frustration and I'm in no way making light of that, I must point out that when you took out insurance, or mobile phone contracts and the like etc, all the detail is in the small print. I know it's no good now, and it's only an infuriating element to you moving back etc, however, legally, you signed the agreement and the onus was on you to check these kinds of things.
I like the idea of dropping down to the cheapest available plan for the phone idea, also if you have it, perhaps sell off the handset that you have and put it towards the cost? with the car insurance, not sure if there's any wiggle room really.
Good luck with your move back and all though !
cheers, DtM! West London & Slough UK!