they take money out your bank without permission

It was my 1st time renting a car from Avis P.E as far as the car goes and the return it was great when collecting the car I had to pay a deposit that was never mentioned, so I used my savings or cancel the deal, on return I was told 5 to 10 days for my refund, its been 2 weeks and I still have not received my deposit, and the best of all 5 days ago Avis debited the rental amount from my bank acc again, without notice,warning,and my consent, but I paid in full on collecting the car! I have called and sent over 50 emails Im lucky to get a response and all I hear is sorry mam, Avis made a mistake the deposit was released but its not in my account there is no manager or head office to get hold off, they took my last money out my account and no day when Il be refunded it s been a horrible experience I will never do this again