I went to the registration to find out that this hotel was only for those who have tickets leaving Terminal 3.
Though I arrived in Terminal 3, as my next flights was to leave from Terminal 2, I could not enter the facility and just had to pay now-show cancellation fee.
That condition was stated somewhere down the small prints, but my usually competent secretary could not realize that.
Expedia should clarify in the name of the hotel or the type of stay "EXCLUSIVE FOR PASSENGERS FLYING OUT OF TERMINAL THREE!"
The local staff was so sympathetic and kind enough to help me reserve another nearby hotel, which I highly appreciate.