@Normen0 @Colleen253 First and foremost, although Airbnb aren't so forgiving/understanding of anyone who's booked for a holiday post March 2020 (judging by what they say), the facts remain that the Covid-19 pandemic has not gone away, and secondly, if Airbnb don't want to repay anyone who's booked a holiday and suddenly been infected, then they shouldn't accept any bookings during a pandemic! They can't have it both ways!
The person who had booked then notified you about having Covid, did the right thing by letting you know (whether she did have the virus or not), but she seems to have gone to an awful amount of subterfuge if all she wanted to do was cancel her booking! and she also appears to be oblivious to the facts of what has to be done when one is infected! - and no, I most certainly wouldn't want her anywhere near my property, for all of the reasons stated.
I'm more than a bit confused by @Colleen253 's comment however about you refunding the Guest rather than Airbnb doing so, for as far as I understood, the latter don't pay any money to the Host until 24hours after the Guests' book in, so how would that work for @Normen0 , especially as if the Guest is reimbursed by the Host, but the Guest doesn't book in, the Host won't receive any money!
Personally I haven't found any difficulty with Community Support, and whilst I accept that sometimes one has to explain the situation several times to C.S. provided everything is explained clearly to them, the problem is usually ironed out to everyone's satisfaction.
Maybe I've just been lucky or fortunate, so in that case I'm grateful I have been!