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 locators (the alphanumeric reservation number associated with your ticket) and, more importantly, 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 ’90s, 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 the United Kingdom, some airlines offer a “courtesy” cancellation if you want to change your flights within a day.
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 also list Expedia’s emails on my site: http://elliott.org/contacts/expedia/.
I contacted Expedia on your behalf and it processed a refund.