Originally Posted by
kayzng
Should I try to call again?
Yes.
From the Qantas
Schedule of Fees web page,
for bookings changed through Qantas Contact Centres the fee is AUD77 for international flights.
According to the fare rules of Oneworld and Global Explorer tickets, airlines can charge this service fee.
If your ticket is a First or Business class ticket, then the fee is waived - "
No Change Booking Fees will apply for changes to a booking in Business or First, including date and time changes." (from the web page linked above)