She cancelled and surely they left already (though still 'enjoying' it?), and now 'someone' at Airbnb feels you should get only $20 per day for the time she did or is staying because of the failure of the AC. Is that the upshot @Kermit0? Is she still there?
Btw, this immediately caught my inquisitive 'eye': "... she's still enjoying the facilities at my private condominium, 24 hour security, swimming, the full window forest views, nicely decorated house with expensive furniture and art collectibles, antiques etc."
This for $72 a night, meaning perhaps low enough you may attract a very rough clientele, IF $72 a night is indeed too low. You are new. I wonder if you are believing the Host Guarantee Airbnb policy word for word and believe it will protect those 'expensive furniture and art collectibles, antiques'. Now that you gotten a glimpse how things are decided by 'Airbnb', it should give a warning that you will encounter more host-guest-Airbnb battles, as things 'happen' (i.e. break some of those beautiful things shown in your pictures).
Making a rental out of one's personal exquisitely-decorated place, has its inherent risks, unless you are equally very careful who end up renting to. Perhaps a higher price is in order, or a stripping of some of those valuables, or both. Just a thought.