Partner Supplier Blame Game

Shocking to say the least. Reserved a room the night before, then had to amend the dates following morning, and Booking.com won't let me change or cancel. When I queried, they said it could be changed with the Partner. When I called the Partner, they said it can be changed with Booking.com. Now I refuse to ever deal with Booking.com, or Balmoral Hotel, Durban again.