They are most certainly to close your accounts, I have just managed to reclaim all bank charges for my son for the last six years from them, and although they paid, he received a notice that they will close his account within 30 days.
Expecting this, he had already opened an account with the post office.
If you intend to try and recover your charges, take heart and ignore all of their letters saying they are not going to refund, stick to the guidelines set out within the site and you should be lucky.