The problem seems to be the global shipping company, where a seller sends their item and the shipping company takes on all responsibility to pack and send.

For some reason, this item has been deemed as not suitable for them to send through the post. If it is classed as a dangerous or prohibited item, they probably won't send it back to the seller either.

I don't think you're going to get this particular item, not unless, by chance, the seller has it returned to them. I doubt you'll get anywhere with ebay in this.

My only suggestion would be that if you come across another item or if this seller gets it back, and you are sure it is not a prohibited import etc, that you ask if the seller can arrange to post direct to you instead of going through a third party.

Also, is there any chance you can source the item in Australia at all, even if it is more expensive?