This is a really old thread, but for anyone searching this query I want to correct this persons answer, because I know from personal experience Australia post is not able to change an address once the item is ordered they can’t simply redirect mail, they don’t allow changes to be made to a parcels address. 
I have encountered this issue myself today! 
you have to lodge an enquiry with auspost and see if they can intercept the item which can be like  a needle in a haystack as international tracking numbers are not always relevant in Australia. When I placed the order my suburb was not in the drop down box, so I chose Melbourne, which is now causing delivery issues