Now really Booking.com

A guest requested a day extra on their booking. That was the email I received from Booking.com I accepted and the change was mad by Booking.com When the Guest Arrived there was a double booking Try to sort this out with Booking.com is a nightmare I asked what was going on, and then I saw the Booking was cancelled Then they emailed me told me I done it Then a request from the guest came to cancel the one night Which I agreed to Bookings still cancelled the entire booking telling us if there are any additional charges we are responsible for that Try to phone the office, they not getting back, Emails are very slow coming in Worst of all they try making it our fault Because they know they are guilty I am not happy right now with Booking.com And what about the guest now????