I booked a flight through JustFly, received a confirmation number, and my credit card was charged. Three days later I received an email (in my spam account) that said my reservation had been cancelled. I called the company and they stated the reservation was cancelled because the fare increased and they wouldn't honor the price I booked it at. They stated it is in their "terms and conditions" that if the fare increases they have the right to increase the fare or release it for resale at a higher price, that it is the airline who changed the price and they don't have to honor their advertised price as it is "out of their control". I spoke with a supervisor and they didn't really care - offered me to re-book through them at a higher price and wouldn't guarantee the price wouldn't change or the same situation wouldn't happen.
I had to re-book (obviously not through them) and the ticket cost me $200 more than if I had booked it elsewhere original day. If I wouldn't have checked my spam account I would have shown up to the airport the day of my flight and not had one. I would highly advise against booking anything through this company!