Advanced non-refundable means just that

Booking.com can not force refunds, all guest houses, hotels etc rely on bookings in place to pay bills that will not stop due to people asking for refunds, this decision will destroy the industry 

We expect you to refund any prepayment and waive any cancellation costs (fees, expenses and/or other amounts) in situations where the guests/travellers requested cancellations as a result of the Forced Circumstances (FC). Booking.com will waive the commission in these cases.