Thanks for your replies guys !
Now I know what the problem is: The Costa Rican government has banned the import of some firearms such as Colt and Bersa. The reasson

? The reasson is just because they can ... ! Sadly for us , our president is simply an irrational antigunner surrounded by a bunch of hoplophobics !
They are trying to ban all kind of firearms in the hands of decent law abiding citizens by rising taxes on guns and ammo , letting people to have only one firearm per household , and increasing legal barriers to purchase a firearm.
But on the other hand a black market of guns is growing up out of control in Costa Rica and criminals have no limits at all !
Can you imagine this happening in the USA

Three years ago we thought it was impossible that somenthig so stupid could happen in Costa Rica ... but it is happening now.