Not sure to which call center AA routes calls from Vietnam, but Spanish-speaking Latin America and Spain go to the Mexico City and Monterrey call centers (although from Spain you can only get through during the Spanish business day and it is not a toll-free number, but a "reduced rate" number). If you have a complicated situation, they can take down your number and call you back when it is resolved, thus saving you a lot of time on hold and a lot of money in phone bills. You should ask if the call center you reach can do the same.