Priceline complaint: Messed up our travel tickets

We had ed reservations for 6 people flying from Lga-Fll. Our flight was at 6:45 am. Upon arriving to airport we were told Priceline cancelled all our prepaid tickets but my sons. He offered to put us on a flight from JFK to Miami leaving at 9:30. First we took 2 ubers to lga ( max 5 people), then had to Uber 2 ubers to jfk. We were scattered around the plane. We arrived in Miami and had to take 2 more ubers to get to FLL to pick up our rental car. We went To visit an elderly family member who died before we got there due to the delay. We’ve called Priceline at least 15 times, they’re rude, they hung up on us and assure us we flew from LGA. I have records of all phone calls, emails, ations, boarding pass to Miami…I called again the other day and asked if they record phone calls they said yes. I said how many calls have u received on this trip they said 1. I asked what it said snd he said that we called bc we missed our flight. No one will help us. We missed the whole purpose of our trip, missed an entire day and spent $600 on ubers. Can you please help. I have all supporting documentation.