someone in mid to upper management at Korean Air who would want to know about errors and mismanagement specifically in Korean Air's Indonesian (Jakarta) telephone reservations department?
I'm afraid that's gonna be tough. No one really cares nor wishes to rock the boat, and no one will really get in trouble since they are expert in blame game. Even you could get hold of the big boys contact, no action will be taken. Or if you are lucky to get the attention of the Chairman, the downline staff will eventually blame all misdeeds on either miscommunication or misunderstanding.
And I can assure you that Jakarta is NOT the only station in need of fixing.