Unauthorised Debit Orders

I have been debited unauthorised more than 6 times, I can't even reverse it. When there is no money in the account, I incur the debit failed fee. When I contact them, all they say is "sorry for the inconvenience". I was promised that I will get my refund but I did not. I was promised that the debit orders were cancelled, but they weren't. I REGRET MY RELATIONSHIP WITH THIS BANK!