Frontier also dropped our August flights two weeks ago with no reschedule options until November. This was the second change as they'd already shifted the flight by a day on both ends of the flight back in May which led me to have to rebook resort days and rental car.
Although JetBlue canceled my replacement flights I'd booked (after Frontier canceled us) yesterday and moved us by 10 hours on each leg. I got one of them changed to the night before and figured we'll just lose a day with the other (we had a 7:45 pm now it's a 9:30 am). I guess these days, expect the unexpected. Such a pain though with hotels, rental cars, etc. I had to make all new plans again last night.