Hertz Hertz Rental Cars Deceptive Sales Fuel Purchase Option Fort Myers Florida

I recently rented a car at Hertz at Southwest Airport in Fort Myers. I purchased the Fuel Purchase Option for $61.93. I was told when I purchased it, that I could bring the car on empty or that if I had remaining gas in the car they would refund the money to me. We brought the car back at 3/4 full. I called and they said they would not refund the money as they say I signed something that agreed to not being paid for the gas. Needless to say there were only 2 agents at counter when we arrived, we waited over an hour in line, and it was hectic. It should of been fully explained by the agent that any gas that we brought back was $$$ in the pocket of Hertz. This was very deceptive.