<recorded message with a female Australian voice> "This is ??? from the NBN. We have been trying to get hold of you as the NBN is now available in your area and if you don't connect within 24 hours, your phone and internet will be cut off. Please press 1 to be connected to a technician."

Considering we've been on the NBN for 18 months, I can only consider this is a scam of some sort.