Q: I booked a round-trip flight from Washington, D.C., to Chicago for Thanksgiving. The original flight was supposed to leave Washington at 10:45 a.m. on Thanksgiving.

When I arrived at the gate, United Airlines announced that a flight attendant did not show up for work that day, and United had no additional flight attendants on reserve. They could not give us an estimated departure time and said that the flight was delayed "indefinitely."

Since it was Thanksgiving morning, I spoke to a ticket agent about other flights going to Chicago. He put me on standby for a 11:45 a.m. flight, which was full, and said I was confirmed on a 12:45 p.m. flight in case my original flight was still delayed beyond 12:45 p.m., but that I would lose my seat on my original flight.

I ended up getting on my original flight and flew to Chicago with a 90-minute delay. When I checked in for my return flight, United had canceled it, because they had no record of me getting on my initial flight to Chicago. I had to pay $386 for a one-way ticket back to Washington.

I e-mailed and asked for a refund of the total, but they refunded my initial round trip purchase of $317, and not my additional $386. I am seeking compensation of the $386 that I had to pay for the one-way ticket.

A: United Airlines should have kept better records. You obviously flew to Chicago for Thanksgiving, and you could prove it by showing them your boarding pass. This was a clerical error on United's part, and United should have fixed it instead of charging you for an extra one-way ticket.

If an airline has no record of you boarding an outbound flight, it will cancel the rest of your journey. Airlines do that to free up empty seats, but also to prevent people from skipping legs of their flight, which can result in lost revenue. So United was just following its own rules.

When you asked United to correct the mistake, it should have paid you the difference between the original flight and the one-way ticket. But apparently that was too difficult. Instead, it just refunded the original ticket, leaving you $69 poorer.

You could have reached out to United through its site or social media to prompt the airline to take a second look at your case. Or you could have contacted a United Airlines supervisor. I list the names, numbers and e-mail of the United Airlines managers on elliott.org.

I contacted United Airlines on your behalf. After your initial complaint, the airline had sent you a $150 flight voucher. After I intervened, United credited you the $69 and also allowed you to keep the voucher.

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