Did you get that rate quoted from the hotel? If that's USD, it sounds exorbitant. Fedex should be able to handle this type of delivery for well under $100 - roll up the jacket/scarf, stick it in a box, send it on a plane.

I wouldn't send anything of value through the Argentinean postal service, but if Gaucho100K feels it's trustworthy enough, I'll defer to him. In the past when I've had to send or receive anything from Latin America, it always went by courier to avoid theft (except to/from Chile, where the postal service is functional.)