As a travel professional, I have access to numerous hotel rate sources. I booked the Hyatt Grand in New York on Booking.com in early October for a stay on December 5. The rate was much lower as a special which was posted for two days in numerous room categories. I booked my room and received my confirmation. I received an email from Booking.com two weeks later that my rate would not be honored by the hotel and would be almost double if I did not agree to cancel it.
I called the hotel and was told to call the revenue department, which I eventually left two messages for. I emailed the hotel manager, spoke with the front desk manager and got nowhere. I cancelled the booking to avoid the higher charge and was offered the opportunity of booking another property for the rate I had found.in New York during Christmas time, I was well aware of the alternatives. Luckily, I had held a backup.
No one could tell me who was at fault, the hotel or Booking.com. I was told that the hotel sets the rates and being their error, was at fault. I use these sites only if certain properties are sold out elsewhere. I will not use them again. I have used Expedia with good luck. I recommend that you do a comparative with the hotel directly before booking on any alternate site. The rates are usually lower.