Your main problem is that you cannot ship any device with a lithium battery by airmail, so it would have to go by seamail or by a very expensive courier that has permission from AP to ship them.

Also an expensive item like the phone from aq new seller is very prone to being targetted by scammers.

Your best action would be to cancel the purchase using "not sent to a country outside Australia" as an excuse.

Edit. G'day lyndal.......................