I think you will care when they take you to court.
Given that the phonecalls people are having with o2, including this one, seem to indicate their customer service is lying/misleading (purposefully or not), I think them taking people to court over such a matter would backfire on them.
At the very least, a quick word with some of the national papers about UK consumers being once again mucked around could publicly humiliate o2, especially if you 'spin' your wording right (or the papers do). Hell, throw in something about being gipped by immigrants and you'll make the Daily Mail's front page. ;-)