I would try to contact them via messages and ask for a mutual cancellation if they aren't able to post, hopefully they will be able to help you one way or another. 

No I appologies I've check the lists and it was one of my other sellers with that on their listing.   Apparently the last Ebay update to my phone changed me over to the US ebay and off of the Australian Ebay

Ohhhhh,I have no idea what you're going to do then.They may just not worry about opening a non payer dispute.

Have you actually tried sending them a message re you didn't realise they didn't post to Australia ?