Frontier Airlines complaint: Cancelled flight and no refund

In March, 2022 we were flying from Arizona to Denver. There was a family that was urgently trying to get home to Denver. Frontier asked for volunteers and no one offered to help. The family was becoming despondent so our family of four offered to take a different flight. In exchange we were given flight vouchers to use on a future Frontier flight. Using our vouchers, we booked flights to Puerto Vallarta for a trip between Christmas and New Years with our extended family. On Saturday, August 27, 2022 Frontier airlines sent an email notifying us that they cancelled our flight and we would not be getting a refund. We have talked to multiple customer service people at Frontier and they keep telling us that there is nothing that can be done. Not only are we now out all the flight vouchers, but now we are forced to pay even higher flight costs on a new airline because flight costs have risen so much.