It's not you who needs to do anything in this situation it is the guest.
You can't refund the guest as you haven't been paid.
Personally for me a guest who acts like this sounds rather flakey so would send up red flags.
How can you not know whether you have booked something to the extent that you incur severe financial penalties.
Message the guest to say you are happy for the booking to be reinstated if that is something she can sort out with Airbnb and leave her to it (if you want her as a guest).