bank account debited but no service rendered

I made reservation online for a car, i went to pick up the car and i was told they do not accept type of bank card i am using(Discovery Bank) i left the shop(Avis Grand Central) and then two days later my bank account was debited by Avis, i phone them to ask why they took money from my account they told me they will reverse the money and its should reflect in my account in 2-3 business days, it been over a week now and i have not received my money. I called the branch again and i was told it now going to take 3 weeks.