Sauce for the gander...?

Virgin Atlantic is refusing to pay airport charges to BAA claiming that they did not get the service they were paying for during the recent disruption caused by snow and ice, particularly at Heathrow.  I think they should be careful,  I do not get my TV, broadband etc. from Virgin Media, but I know a couple of people who do, and they regularly complain about what they perceive as bad service - so are they entitled to withhold payment?