WolfvanWeen

You have different options:
1) Use a business class redemption. Your screenshot shows that there are availabilities.
2) Check single flights, e.g. SJO-BOG & BOG-MAD. If you see availabilities on all four single flights, you can try with the call-center. If there aren't any either, no chance.
3) Try other airports (e.g. BCN instead of MAD - there are cheap train, bus and other connections, e.g. BlaBlaCar)
4) Try other dates (of course...)
5) If there's a connection with one airline only (e.g. in your case there's a direct flight option with Iberia), see if you get different results by specifying that airline in the search mask.
6) Wait. Some seats are only made available T-14 or similar.