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As far as the Low Fare Guarantee, here are the T&Cs from F9..
If you read the T&Cs, you will notice the part that I bolded. If you find a lower fare on the same day, then you can submit a claim. However, you found a lower fare three days after you booked your ticket. F9 is not at fault here. I don't see why you would not fly F9 because they won't honor your request for a refund, outside of the refund period.
Quote:
LOW FARE GUARANTEE
Don't bother searching the Internet for countless hours trying to find the lowest Frontier fare. Just visit our website, the home of our Low Fare Guarantee! If you find a lower Frontier fare on another website on the same day as making a reservation on FrontierAirlines.com for the exact same itinerary and exact same fare type (Economy, Classic, or Classic Plus), we will credit your EarlyReturnsŪ account with 2,500 miles. To submit a claim, make sure you follow these simple steps:
1. Book your flight reservation on FrontierAirlines.com.
2. On the same day, find a lower Frontier fare on another web site that is at least $5 one-way or $10 roundtrip less per person than the fare purchased on FrontierAirlines.com for the exact same flights, days and fare type (Economy, Classic or Classic Plus).
3. Capture the web address (URL) of the site where you found the lower Frontier fare and make a screen shot of the itinerary confirmation page (not the search results page) as well as the fare rules and restrictions information for the lower Frontier fare. These pages will typically be found one step prior to the purchase page.
4. Fill out our online form and retain all of the necessary information for verification of your claim.
5. Once confirmed, your EarlyReturnsŪ account will be credited 2,500 miles. Not a member of EarlyReturnsŪ? Join now.
http://www.frontierairlines.com/fron...e-guarantee.do