Bookings refuses to refund

I have done a booking for a holiday home on the website but the date I have entered on the website and the confirmation I got was were not the same I called booking.com to rectify this and sent them numerous messages via customer services but never got the response so I called the property owner to cancel but said that can only be done on the website, when I finally managed to do that it was the day they chose for me which I didn't nt want but they did not respond as I want to be refunded... Until now no response from them.