why keep customers banking details?

I rented a car at Avis in July and got my deposit and all. Then yesterday i get a sms that Avis has deducted R260 from my account. I called this morning and they said it was for a traffic fine. Should that traffic fine not be just moved to my name instead of you debiting my account. I'm very uncomfortable with the fact that you can debit my account as you please. Had i known that you actually keep people's banking details i would have used other payment methods.Im really concerned it feels like an unauthorised debit order.The thought of you taking money from my account as you please without even consulting me first really doesn't sit well with me. And how long are you going to keep my banking details in your system?