Q: I recently booked one airline ticket through Expedia. At least that's what I thought. I paid $310 for what I thought was one ticket, but when I was using the site, it felt a bit slow. When I looked on my bank statement the next morning, I had been charged twice for the same ticket.

I've called Expedia four times over the past two days, e-mailed two different representatives, and contacted them on Facebook and Twitter. But they claim the extra charge does not appear on their database and that therefore they have no obligation to refund me.

My bank says I should get in touch with the vendor, which I have. The subject heading for both charges is identical.

I need this extra charge deleted. I live on a very tight budget and these kinds of things make my life far more difficult than it needs to be.

A: It's difficult to tell if this was an actual charge or just a phantom double-charge. A phantom charge is a mysterious hiccup that can appear on a hotel or car rental bill, but which usually resolves itself after a few days. I've experienced it a time or two.

On the other hand, if you were actually double-charged, then you would also have two separate record locaters (the alphanumeric reservation number associated with your ticket) and, more important, Expedia would be able to see the problem on its side. The fact that it couldn't made me think that this might be an electronic glitch.

The "website running slow" scenario is an old standard from the 1990s, as far as travel complaints go. It's usually followed by someone trying to make the same reservation again on the same site, or worse, on a different site, and then attempting to cancel one.

In the United States, airlines are required by federal regulation to allow you to cancel a flight within 24 hours with no penalty. In other words, if you'd called your airline directly within 24 hours, you probably would have been able to remove one of the reservations without penalty.

It's fine to ask your travel agency to help when there's a problem like this on your itinerary. But Expedia was right; you should have phoned your airline to get this fixed. I contacted Expedia on your behalf and it processed a refund.

Christopher Elliott is the ombudsman for National Geographic Traveler magazine. Read more tips on his blog, elliott.org or e-mail him at chris@elliott.org.