Sorry just noticed the answer from Stu Dent.
Why would OFCOM get involved? There are absolutely NO grounds for a complaint. O2 didn't force the connection nor did they ask for payment for something trcfp hasn't used. This is purely a case of not taking the trouble to understand the icons on the phone. It isn't O2's fault that trcfp ignored something designed to inform the user of a service being connected. As much as it hurts, this isn't the fault of anyone but the end user. There are loads of things you can do to stop this happening in the first place.
If you went away on holiday and left the central heating running full blast and all the lights on and all the appliances running would you expect the gas and electricity bills to be more expensive? Yep you sure would.