Strange: GlobalExchange refusal to exchange money. (San José)

I live in Santiago (Chile) and last week, arriving for a vacation trip to Costa Rica, could not exchange Protected content at S. José´s International Airport. The Global Exchange guys told me they would not do it, after seeing I held a diplomatic passport. I found it so weird that I complained to Costa Rica´s Tourism Board, who promised to investigate. Anyway, I managed to hail a taxi and pay in dollars. Has anyone had a similar experience?