We arrived there at 15h00 and there was no one to assist us with our booking

We arrived there at 15h00 and there was no one to assist us with our booking. Eventually I found a girl in a room watching Tv. She said she was the manager. She took us to our room and what we found was shocking. The fridge was filthy. The bedding was definitely not fresh and it was dirty. The shower floor was discusting. I phoned the owner to complain and he was very rude to me and just told me if I’m not happy I must ask Booking.com to refund me. We left and paid to be accommode at another guesthouse. I tried to contacted Booking.com but nowhere on there website is any contact information. Their email does not work at all. Please help