Frontier Airlines Frontier Airlines web/phone bait and switch Internet

I booked a flight to Colorado Springs on Frontier Airlines for a weekend, set to return Saturday morning. After receiving an invitation to an event in CS for Saturday, I went online to see about changing my return flight to Sunday. The website quoted me $50 to change my return flight, since the flight was exactly the same and had open seats - it was just the charge for the change and nothing more. Seeing this, I replied to the invitation that I would attend, and I continued to book my changed flight.

Well, their website took all of my payment details and authorized my credit card but then gave me an error message that it could not be completed and I would have to call to change my ticket instead.  Okay, no problem. I called the number provided, but the woman on the phone said the cost would be double what the website had just quoted me. I thought maybe the price had changed in just the 10 minutes between my attempted online purchase and calling, but when I tried it again, the website showed me $50.  Brenda, the customer service representative, said she saw that price too but was unable to do anything about it. After arguing with her on the phone for close to an hour, she gave me a number to call and complain about the price difference, and I allowed her to change my ticket.

When I called the number she had provided me, a couple of days later (it was late at night when I finished changing my flight finally), Todd told me that I had already accepted the higher fee and that the time for disputing the cost was over. He would not budge, even though I have print screens showing what the website said at the time of my charge, as well as of my credit card being authorized for both amounts - for the exact same flight. Both he and Brenda admitted knowing that the "website doesn't always work" but they absolutely refused to honor the price advertised.