Unfair Practices by Misty Mountain in Sabie

I made a booking at misty mountain in sabie via booking.com on the 2nd of January 2023 for 2sleeper unit when i received a confirmation for a booking it came back showing the booking is for 1 adult i'ts now their error my suffering as when I cancel on the same day they are unfairly charging me 50% of money I paid as cancelation and penalty fee of their error as per property owner of misty mountain, I find it absurd to put it mildly and asking myself how such establishment qualified to register with booking.com, the only fair practice is to refund the full amount as i'm not responsible for the mistake that occured in their system.