Same payout after guest shortens stay?

I have a guest who has been staying with us since September with a scheduled departure in early January. Today, without saying a thing, he sends us a request to change his reservation with a departure of tomorrow. After checking the cameras, it looks like they left today. They brought a u-haul and packed up some furniture they'd brought with them (none of ours) and both of their cars and the u-haul are gone. They've mostly been home bodies, so I'm pretty sure they're out for good. The reservation request shortens their departure from early Jan to tomorrow, but it says that the payout is the same for us even if we accept the change. In two weeks from now we were scheduled to get another $5K from them. A hurricane trashed our fence, and we ended up having to replace that during their stay and we really need that last $5K to cover bills until our next guests are scheduled to arrive. They're also leaving, unexpectedly, right before the holiday season, which really sucks, cause it will be hard to get it booked this close.

Have any hosts been in a situation like this? Is airbnb REALLY going to collect another $5K from these people when they're not even at our place and they're going to give that to us? Or are the guests going to cancel their credit card and then airbnb will tell us they haven't collected that $5K so we won't be receiving it? We have a strict cancellation policy and once we had a guest cancel the day before they were supposed to show up and airbnb stiffed us on our payment saying the guest hadn't paid them the full amount, so they couldn't give us more than what they had. So I'm worried about accepting this reservation change, because maybe airbnb will pull that same crap (maybe they will regardless?). Before they stayed with us the guest specifically asked what happened if they cancel before the end of their stay and I sent him to a link with airbnb's policy where you can only shorten it to a month from when you do the reservation change request and once you get to 28 days from the scheduled end of the stay, you can't get any kind of refund. So the payout not changing is in line with airbnb's stated policy, and the guest was aware of this fact before booking with us and obviously suspected it might come into play. I've just been burned by airbnb with stuff like this before and wanted to see if anyone had any luck getting airbnb to pay when guests aren't actually at your place.