Traveling to south america alone?

Hi, I am a minor of age 17, i have a valid ID Card, and pport, i am traveling for 1 month to chile alone, my parents went to the consular of chile and signed a paper saying it was ok for me to travel alone and that they would drop me off at the airport and my family would be waiting for me in chile, now then i recently (a few hours ago) found out that i might need to get a paper signed for the airport, saying that they give me permission to travel alone, also i have a valid visa before any1 says anything, back to the main point, do i need this contract or is the chilean consular form all i need? if i need the contract from the airport, can i get it there and fill it out there with my parents? also this is not for people to port their opinions and junk, im just here for straight to the point answer, because i am traveling tomorrow!!