Booking.com - ****MERS!!!!

There is NO rating for Booking.com. They overcharged my card by Z****50!!! for a reservation at the Hilton Namibie. AND The accommodation I booked in Namibie did not receive their payment from Booking.com and I'm left with a card charge of ZAR8760. But the confirmation from Boooking.com state an amount of ZAR3410.00. (which was not paid to the accommodation any way!) I have mailed over and over again, I have sent my bank statement to proof to them that I was overcharged, and NO ONE is responding. The Hilton Windhoek, informed me that I will pay in full when I arrive, because they have not received ANY PAYMENT from Booking.com for my reservation!!! But that cannot be because I was charged by Booking.com and overcharged as well. How can this be. The person's name is Kai from Booking.com. But he has now disappeared from the face of the earth. I need my full refund ASAP. I will then pay when I arrive at the Hilton. But I cannot Pay twice! I don't know what to do. The message system on Booking.com suck, no response, no reply! Please help me I need this people to refund me my money. This is the worst service I ever got in my life, making travel bookings. I will never EVER recommend Booking.co for any international reservation!! they are the worst!