Charged boudle!

I made a purchase using my debit card and somehow the amount was deducted twice from my account!! Now the bank cant stop or reverse the one payment, i apparently need to fill in forms for a dispute and all sorts of stories, plus pay a fee!!! How the hell do i have 2 pay a fee for a mistake that is not mine?? This bank is useless and disappoints me time and time again. I think it is time to move to a proper bank. Pathetic.