You are the second person from Australia who has been trying to contact Airbnb in the last 24 hours on this forum.
Did you try this number for Airbnb in Australia: 02 8520 3333 (international 61 2 8520 3333)?
Many people have had great success posting on Twitter with the @AirbnbHelp handle. They will then ask you to DM (direct message) them. It has worked wonders for many especially since you have tried calling.