When listing an item for sale, under the Postage section, the default setting is to only post to Australia. ( No international postage appears as default for International ) If you follow the international postage prompts you can set your listing to post wordwide or to exclude cetain countries or regions. If you decide to exclude a certain region you will need to check a box ie. United States, and your item will not be available there. You also need to enter a flat rate postage cost for worldwide ( usually used for letter type items ) or add the size and weight dimensions for the postage calculator to work out your postage cost. Have you done any of these changes ?. If not I would follow the previous advice and ensure you are on the Australian ebay site. Sometimes ebay will take you to another countries site, mid listing process if you look at other listed items while listing. ( to see other items in a catagory you have selected etc. ) . Ebay then can keep you locked into the new site while you complete the listing, returning to Australia once you sign out and back in again.  Just another Glitch.