Wyndham Foz do Iguacu
 

That's a problem I've seen with other WR properties in Argentina for months. For example, do a search around Lujan, and the first two hotels (HJ Lugan and HJ Pilar) never show availability on WR's site (though they do show availability on third-party sites), and it's been like that for months now.

So I'm not sure what's going on, but it might not mean the hotel is leaving. You might have call WR on the phone (and maybe elevate to a supervisor?) to get a decent answer.

(In my case, I found through reviews that the HJs near Lujan are far from the best hotels in the area, so I stopped caring that they never have availability. And that's why I didn't look further into it myself.)

This has happened to me in several properties in the states. I think the owners have the opportunity to option out of participation through the app. The points bonus must debit from the property in some way. Obviously I would think that the app would bring more business but I am sure there are exceptions.