I believe a transaction isnt finished until the buyer has received the goods and is 100% happy.

It is the seller's responsibilty to ensure the goods reach the buyer. If the goods go astray in the mail it is up to seller to approach Aust Post and put in a claim.

Sellers can no longer leave neg feedback for buyers so I cant see what the OP means by 'holding buyers to ransom'. nicegreen is right about the star system being anonymous.