I have been using Click and Send for 12 months or so without a problem. In the years I have been selling on Ebay I have had one item that the buyer said he never  recieved but I suspect it was at his end. I was a to a Sydney suburb with a slissy reputaion. I know one of my supplier personally who operate in a bush area, who have outmail picked up by the postie who lost hundreds of dollars worth of outgong orders till they put a lock on the post box and gave the postie a key!  Ever since that I always select "if unattended, leave a card in the mailbox to collect at nearst Post Office" . I also ensure that the declaration is signed and that I recieve a lodgement reciept. That way there documentation and that equal proof in writing. I would be making some waves in Aust Post for a full investigaion with that many lost. Someone knows you in Aust post and are waiting for your orders! Probably locally.