ok cheers for your help

hi there everyone!! just wondered if anybody could help me, natwest have been taking these bank charges out of my bank for about three months non stop as every time they take out a bank charge it takes me over my overdraft then they take out the charge for goin over my overdraft so i am currently £900 overdrawn!!! does anybody know the email address i can send the letter to claim back all the charges??? thank alot