If you sent it trackable at this end then once it reaches the shores of another country it will no longer be trackable.. Aus post has never been able to do this and now it offers no tracking at all on international items. Problem is not with the german postal service.. its is the shortfall of the Australian. I can still order from USA and have it tracked right to my door and follow online... this is not possible with Aus Post.
Ive had the same problems with stencils... big delays once on foreign soil but all have reached their destination.. it just took time that's all.
Chances are that your parcel will arrive.. in the meantime Paypal will freeze your account and it is up to you to prove that the parcel arrived. you can ONLY do this if the recipient tells Paypal it arrived.. no other way. When Paypal did this to me and took all my funds I had a digital signed receipt to prove it had arrived.. didn't matter a shot unless the recipient actually tells them.
Paypal allows for buyers to rip off sellers.. you have no way at all to prove you are not ripping people off.. this is why Mike hates Paypal and its for good reason.
Only option you have in the future is to send DHL or similar trackable service... never leave money in your Paypal account.. that way they can never take all your funds, or avoid Paypal altogether and use Western Union etc.
Chin up mate.. what you are doing is great but Aus Post and Paypal will leave you hanging out to dry..