challenge the usage.be a thorn in their side.
I often question their phone bills , as ours is always around 70 quid per quarter, and it's a bloody ornament we don't use it.This is despite us being on the number 1 package or whatever they call it.
Isn't the base package something like £11 a month?
It wouldn't surprise me if they mess up the settings, i wonder how many people know how much they've used.