Q: I rented a car from Hertz in Miami a few months ago. Before returning it, I filled it up with gas. When I turned the car in, I double-checked the fuel gauge, made sure my receipt reflected that the car had been returned full, and, thinking I had myself covered, flew home.

A few days later I received a letter from Hertz saying I had been charged $93 for refueling. It went on to say that their own receipt that stated the gauge was full, was not ample proof that I had refueled the car and I would need to provide a receipt.

I paid for the gas with cash and did not keep my receipt.

I was aghast that I was not protected by their own paperwork and the burden of proof was on me to produce a receipt.

What can I do? I've called Hertz numerous times to no avail. Am I just a victim of their latest scam? Do you think it is fair for them to disregard their own receipt as proof that the car was refueled?

— Danny Griffin, Los Angeles

A: No, that's not fair. If Hertz gives you a receipt that verifies your car was returned with a full tank, then that should be the end of the story. Case closed.

It's true that car rental companies are getting strict about cars that are returned with less than a full tank. Some companies make you show them a receipt when you bring back the car. That's fine.

But making you show a receipt after you've settled up? I've never heard of that until now.

How did this happen? It's possible that the Hertz agent checking you in didn't pay attention to the gas gauge and printed your receipt. Later, another associate discovered that the needle on your gas gauge was tilting toward the "E" and decided to charge you.

I think a $93 bill is a tad excessive. That's a very generous markup and probably more than covers Hertz's cost to top off your tank. I can't blame you for thinking it's a scam.

Here's what you have to remember the next time you rent a car: When you refuel, use a credit card and ask for a paper receipt. Keep the receipt and show it to the employee when you return the car. You might want to ask if it's enough proof of a full tank, and if it's not, what you would need to do in order to avoid a refueling charge.

I contacted Hertz on your behalf. It refunded your $93.

Christopher Elliott is the ombudsman for National Geographic Traveler magazine and the co-founder of the Consumer Travel Alliance. His column runs twice a week at seattletimes.com/travel Contact him at chris@elliott.org.