Q: Before the pandemic, I used the Orbitz app to book a hotel during our vacation at Disneyland Paris. At checkout, I attempted to pay with PayPal. The Orbitz app said my attempt failed.

After reaching out to Orbitz to confirm that I didn't have a reservation, I tried again. It failed again. But later that day, I received an e-mail notification stating that both bookings went through — even though Orbitz said they hadn't.

After contacting Orbitz by phone, e-mail and Facebook, they're refusing to waive the cancellation fees even though they're at fault. Can you help me get a refund?

A: If Orbitz said you didn't have a reservation, then you shouldn't have had a reservation. But you did. How can that be?

I've encountered this problem several times. Online agencies have systems that try to confirm a payment method. When they fail, they just keep trying. That's what appears to have happened to you. The customer service representative also saw no reservation at the time, which was true. Until it wasn't.

So what should you do before you initiate another reservation? My advice is to get the denial in writing (by text or e-mail) from the online agency. Don't ask by phone, because you don't have a record of that conversation. So, if you end up with a duplicate reservation, you're out of luck.

By the way, this isn't a problem for airline reservations made in the U.S. The Department of Transportation has a 24-hour cancellation rule for most airline tickets. So, if you mistakenly double-book, you can cancel right away and get a full refund.

But there's another reason why your case wasn't so simple. I'll get to that in a minute.

Online agencies often rely on antiquated reservations systems and payment systems that can be glitchy. But someone has to take responsibility for a double-booking like yours, and I don't think it should be you.

You can contact an Orbitz executive if you're not getting the help you need. I list the names, numbers and e-mail addresses of Orbitz managers (Expedia owns Orbitz) on my consumer advocacy site, elliott.org.

I contacted Orbitz on your behalf. Its records indicate that you used two different Orbitz accounts with two different e-mails to make a reservation at the hotel. That resulted in duplicate bookings at the same hotel, because the agency couldn't have known that both reservations were for the same person.

It looks like Orbitz already found your second reservation, waived its cancellation penalties and refunded the duplicate booking. After my inquiry, the company found your second reservation and waived its cancellation penalties, resulting in a full refund.

Christopher Elliott is the founder of Elliott Advocacy, a nonprofit consumer organization. Contact him at elliott.org/help or chris@elliott.org.