I personally would use the tracking option. I had an order go missing en route to Germany, untracked, and thankfully my buyer was understanding and was willing to try and find it before asking for a refund. Thankfully, I got a message last night saying it had finally arrived (after 5 weeks). Prior to the message I had asked on the Aust Post facebook page if there was any way of finding where it was and this is the reply they gave me:
"Unfortunlatey unless an item is sent using a traceable service, there is no possible way to determine its current location or status. If the item were refused entry by the German customs service it would be returned to sender or the addressee would receive notification."

So yes, from now on I will only send tracked items overseas.