Shame On Booking.com! You Ruined My Trip

I had booked 2 flats for my students in Bergen, Norway, and paid in advance. Today when we arrived in Bergen around 11 a.m., we called the property "Broadergarden." The property owner said they wouldn't host us because Booking.com had made an overbooking, and they had no available flats. Booking.com didn't inform us about this, and I had nowhere to go in Bergen with 10 students. Both "Broadergarden" on Booking.com and Booking.com caused us to have a hard time, and we had nowhere to go in the rain with our luggage. What a working ethic this is! Both sides are blaming each other. I want to complain about both of them because right now, despite paying a very high price, I am staying at a camping site under bad conditions with 10 students. There's no toilet inside, no heating.