I had the same thing where they didnt send me the credit card statements - I sent them an online request and was told that I would receive them within 7 days.... didn't receive them so wrote to the commissioner to give them a kick! still waiting though...

Hi - normally companies will ask for a minimim of 2 weeks notice of change to payment details (especially if correspondance is by post) mainly because the company has to inform the bank on your behalf which can take up to a week and once that has been changed the BACS payment must be ready to go 3 days before its due in the bank - if you only gave the company a couple of days to organise the change then I think the charge will stand as they have probably been charge by the banks themselves (although I doubt it would make a dent in their profits).