I recently rented a pickup truck through National Rent-a-Car in Berkeley for a one-way move to Walla Walla, Wash. The two-day trip went smoothly, and we loaded and unloaded the truck without incident.

When I returned the vehicle to the rental agency, I did a thorough walkaround, and found not one iota of damage. I cleaned the interior, and opened and closed the back gate to check for any left-behind items, and found the truck bed in exactly the same condition I rented it in.

I brought the keys to the counter, and the agent accepted them, and told me they would send me my final invoice. No one was in the lot to check the condition of the truck with me and verify the condition of the truck.

A few months later, I got a call from a collection agent at Enterprise, which owns National. He said there had been $750 worth of damage to the truck's back gate and left rear side.

I was shocked. When they finally sent me the documents, they showed massive damage to the rear gate. There also appeared to be some sort of collision damage. The repairs were executed months after my rental.

I told him I couldn't have done it. They refuse to hear from me or treat the case as anything but an opportunity for monetary gain, and I was dumb enough not to have photographed the truck or have them do a full inspection.

As of today they will be sending the bill to collections, so unless they hear reason I will be harassed and my credit possibly damaged. This is really a nightmare for me, in part because I find myself so helpless to the wolfish and questionable practices Enterprise Holdings and National Rent-a-Car has employed.

How is this allowable, legally? What are my options for pressing my case?

– Dan Anthony, Eugene, Ore.

National's efforts to collect damages from customers who damage its cars is completely legal. Coming after you, however, is another question.

Here are a few things that concern me about your case: First, the timing. A lot of time had passed between the time of your rental and the repairs and subsequent damage claim. That's highly unusual. Damages to a rental car should be identified at the time of your return, and the repairs should be made promptly – not months later.

Second, I'm troubled by what you say was National's attitude. An ethical damage claim must include a credible appeals process. It sounds to me as if your complaints were simply dismissed.

National should have shown you time-stamped photos of the damage to the truck immediately after your rental, a repair estimate and an invoice from the body shop. It sounds to me like there were some paperwork problems.

And not just on the car rental company's part. As you say, you should have photographed the truck, both before and after the rental. Use the digital camera on your phone or shoot video, but whatever you do, get some evidence of pre- existing damage or of the fact that you returned the car in good condition.

Also, you shouldn't have accepted the agent's assurance that everything was fine and that an invoice would be sent to you. Next time that happens, ask for a manager and conduct a walkaround. Get the manager to sign the receipt and, if possible, to indicate in writing that the vehicle was returned in acceptable condition. That limits any future claims.

No one is trying to get out of paying a bill here. It's just that you want to make sure you're paying your bill, not someone else's.

I asked National about your case, and a representative contacted you, and said proper procedures hadn't been followed in your case. They dropped their claim against you.

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Christopher Elliott is the author of "Scammed: How to Save Your Money and Find Better Service in a World of Schemes, Swindles, and Shady Deals" (Wiley, $24.95, 256 pages). He's also the ombudsman for National Geographic Traveler magazine and the co-founder of the Consumer Travel Alliance, a nonprofit organization that advocates for travelers. You can read more tips on his blog, elliott.org or email him at chris@elliott.org.

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