Booking.com *****

I attempted to make a booking on booking.com, subsequently their site showed an internal server error, transaction has gone off my credit card but I have no booking confirmation or reservation. I have tried to contact them by email so many times, tried to call them - and the phone was just put down on me on numerous occasions. This is *****. My bank says the merchant needs to reverse on their side however I am not able to even have a conversation with the correct person at booking.com, they apologize, then write the same mail back asking for exactly the same information which I have provided them over and over. this is absolutely disgusting.