FrontierAirlines cost me my flight back with perk bundle, another ticket with another (but reliable) airline and a hotel night. I checked in online few hours prior to my MIA to PHL. I have TSA Pre check, when I got there, FrontierAirlines would not load my flights or find my boarding pass. This used to happen at times, FrontierAirlines would have forget who I was. This time, it was critical and FrontierAirlines kept giving me an error. Come to find out, other passengers on the same flight had the same issue. We headed to Frontier counter 35 minutes before departure, no one to be found, we were told by other airlines representatives that frontier personal left about 15 minutes prior!!
We called frontier, after a looong wait, we were told that we will miss the flight, that the flight is not refundable, we have to pay a $110 fee to be placed on another flight 2 DAYS LATER!! other passengers managed to get a credit for their missed flight, I was not as lucky, and person I spoke with told me IT WAS MY FAULT TO TRUST THEIR APP WITH MY BOARDING PASS!!
To add insult to injury, frontier lost my suitcase on the way to MIA (direct flight). They found it yet 5 days after my flight and I am still waiting for my bag back.
I will never FlyFrontier again. Do yourself a favor and print your boarding pass or at least take a screenshot. Better yet spend a little more and travel with a real airline in peace.