Airbnb will consider that you have to discount 50% -70% discount or allow the guest to cancel for free.
I once had guests that complained about slow internet (not broken, just slow, their word against mine because every time I went over it worked fine) and Airbnb made me refund 300 euros on a 700 euro stay.
You can't advertise a pool property then not provide the pool, even if it's not your fault.
You have to fix it asap and in the meantime offer a large discount or the possibility of the guest to cancel.
You can contact client support and explain, they will help your guests find alternative lodging.