I wish I could give zero stars. I booked a flight online with Frontier to Denver over a week ago for my boyfriend and me, when the flights were reasonable (approx. $80 one way each before any of the ridiculous add-ons). I entered my credit card information and received a confirmation number. Yesterday, I was double-checking my flight time on the website and asked for a follow up e-mail confirmation because I had not received one. On the e-mail confirmation (which included my confirmation number!), it said my card was declined. I called customer service and could barely understand the customer service agent or her supervisor (the call is obviously transferred straight to another country). The gist of what they said is that my billing address was not entered correctly when I booked (even though it was), so it did not process (even though I received a confirmation number) and they had no flight booked for us and we would have to book a new flight. Of course, by then, the flight price had gone up to over $350, $700 for both of us. They refused to honor the price I had initially booked for, even though they had open seats, and refused to acknowledge the fact that it was completely messed up that I received a confirmation number and had every reason to believe my flight was booked. I will Never use this airline. Thank god I tried to pull my reservation or I would have been very upset at the airport at 6 a.m. trying to check in for my flight.