Why did Frontier make me pay extra for my bags?

QA: If Lookupfare.com sold you a ticket that included checked bags, then you shouldn’t have to pay for the bags. Period.

So, why did you? I looked up your flight from Madison to Las Vegas and saw no checked bag included. You did the right thing by making a printout of the agreement; at least that got you to Sin City without having to pay $100.

By the way, these luggage fees are a little ridiculous. A decade ago, every airline ticket included at least one checked bag.

Now airlines are raking in billions of dollars in extra profit by charging extra — in some cases way too much — for the privilege of taking a bag or getting an assigned seat.

But that’s the world we travel in. We play by the airline’s rules, but we also expect the airline to follow

its own rules. That’s why a case like yours is particularly upsetting. Lookupfare.com sold you two checked bags, and then Frontier didn’t honor its agreement.

You could have contacted one of the customer service executives at Frontier Airlines. I list the names, numbers and email addresses of the key managers on my consumer advocacy site.

It looks as if you did try calling your online agency, Lookupfare.com ,and the airline. While a phone call is a great way to resolve an urgent problem — such as when your airline cancels your flight and you need to be rebooked — it’s not ideal for this type of case. I always recommend keeping a meticulous paper trail and getting every response in writing.

I reached out to Frontier to find out what happened.

I recently bought roundtrip tickets from Madison, Wisconsin, to Las Vegas on Frontier Airlines through Lookupfare.com. The tickets included checked bags for both of us. I have the printed itinerary that shows the baggage is included.

On the return flight from Las Vegas, Frontier made me pay $100 for the two bags. I can’t get anywhere with either Frontier or Lookupfare.com. I’m wondering what to do next. There must be some way to get my $100 back. It turns out that you did, indeed, have two bags included in your fare. But you changed your return flight from Las Vegas to Madison.

“When she changed her flight date, it also canceled the bags and that appears to be the root of the problem,” a Frontier spokesperson told me.

Frontier will refund the difference between the online bag fee and atairport bag fee. Hopefully, Frontier will fix its system, so that in the future, a changed itinerary won’t result in a dropped baggage fee.

Christopher Elliott is the ombudsman for National Geographic Traveler magazine and the author of “How to Be the World’s Smartest Traveler.” You can read more travel tips on his blog, elliott.org, or email him at chris@elliott.org.