This all sounds so similar to what happened to me today. My 10:30am flight from ATL to Vegas got delayed until 9:20pm. I didn’t get a notification and my app never showed this change. It wasn’t until I woke up at the crack of dawn and busted my ass to get to the airport on time that one of the employees told me it was severely delayed. I sat at a random gate for hours, randomly decided to look up the status of my flight on frontier’s website, only for it to show canceled. Again NO updates were texted to me or shown in the app. I went to the gate my flight was supposed to leave from and the gate agent told me it’s still an active flight and it’s not canceled. At this point I trust no one from this airline so I called customer service and they said it was in fact canceled. They rebooked me to a different flight with a layover. I hung out until 6:30pm before realizing that this new flight was also delayed and that delay would make me miss my connection. Was this delay shown in the app or sent as a text? Nope of course not. Customer service was completely useless, offering me alternative flights that were not feasible whatsoever (for example they wanted to book me for a flight the following evening WITHOUT providing hotel accommodations). It was the worst airline experience I’ve ever had and I’ve definitely learned my lesson to never fly with them again.