Last year I booked a BKK-ICN-LAX-ICN-BKK on the OZ web site, and it would not accept my US-based VISA card. I called the BKK office and they could not accept it over the phone, but would accept it if I went into Bangkok to the city ticket office. I live a few hours away from Bangkok and decided to not make a trip just to buy the ticket. Expedia had the same flights for the same fare, so I booked with them (and paid with the US VISA card) and held my breath that there would be no schedule changes or IRROPS that would require me to deal further with Expedia.