Qatar uses the Oryx Garden Hotel which cannot be booked online. Rooms being sold online would have been for the Oryx Hotel which Qatar doesn't use.

How did you find the staff at the Transit counter? I'm in the opposite situation to you. I have a 20 hour layover and I've been assigned the Oryx Garden Hotel. With a layover of that length, I'd prefer to be in the city to do some exploring on my layover, rather than at the airport. Were you provided options or able to make requests? Also travelling business class.