@Diane749 wait, are you saying the guest is still in your home??? If so, you really do have a problem. If they are not leaving, then you should call the police immediately for trespassing.
My term indignant was used in reference to my initial interpretation of your post, which was that Airbnb cancelled the guest and then took 6 hours to clear your calendar. Now I see that your calendar is still blocked.
Regarding 'Awaiting Payment': this shows up on your list of reservations when you look on your phone or computer. Confirmed bookings switch to green, but unconfirmed bookings remain in black and it clearly states at the top of the booking 'Awaiting payment'. This would have raised alarm bells for me immediately, especially if the guest was checking in the following day.