Fourth Week and my deposit still not paid

On the 18th of September I rented a car at Dollar Thrifty and paid a deposit. My deposit has not been released back since then. When I go to their offices they tell me they reversed the transaction but no one can give me proof of this. They tell me the transaction was done using a system that does not produce slips. Why in the hell do you even have such a system because now you cannot hand me proof. I am very p***ed off at the way you do things and your service. I wish I had looked for complaints about your company before I made use of your services.