That really sucks but doesn't suprise me - an ex of mine worked there and he was told to put the payment protection insurance on people's cards unless they said a VERY specific phrase (ie 'no thanks i don't want it' didn't count).
If you can, it might be worth getting a second card and threatening to switch to this user and close your account - they really dont like you to do this (ask to speak to a supervisor they have more power), and it might just mean that they waive some fees/ reduce your interest rate (they did this with me and a late fee once, and again when i threatened just this) - they hate to loose custom; especially now i should think!.
Of course you would need to be able to get a second card as stand-by so it isnt just a bluff, and actually switch if they dont play ball (it might be worth the transfer fee, just to stop MBNA making money off you). GOOD LUCK!