I wanted to share my recent misadventures with booking.com so that the same thing will not happen to you.
I booked a hotel for Marseille in October 2015. The room booked (Hotel le Vieux port) was indicated as a 2 adults + 2 children room. But, when I arrived, the room was only for 2 adults and one child! I contacted booking.com by phone about that issue and their agent admitted the responsibility of booking.com. She ensured me I would be refunded and found me another hotel (for which I paid again). After a few months I checked my statements and saw no refund. I contacted the customer service, but booking.com is now refusing to refund me pretexting that the hotel does not want to refund them!