If you rented out the points here, typically the payment is made in full before the reservation within 90 days. You have no recourse if your renters don’t pay you after the stay. On the other hand, you can cancel the reservation and rent to someone else if the renter refuses to pay. I’d reach out to the renter and ask them to pay immediately, per normal convention in renting points directly from owners.
I know renting out on your own can be intimidating, I’ve been there back when I stared in 2013 or so. But it really isn’t, the process is pretty straight forward. You joined in 2009 and is a reputable forum member here with a long history. I don’t think you will have trouble finding renters willing to pay you up front.
EDIT oh nevermind - I misread your message and thought you rented out your points here, but the renter won’t pay you until after the stay. You rented out through an intermediary so they already have the money, they just won’t pay you until after the stay. In that case it’s safe. Sorry for the misread!