Oooh well I can see why the seller has told you to file a claim. Because as far as he's concerned once it reaches the Global Shipping warehouse it's their responsibility.
I had a problem where my item arrived damaged. I reported this to the seller and she basically said it left her hands in good condition so the Global Shipping warehouse must have damaged it when re-packing. Same thing, she basically said 'file a claim'
I filed a claim and got my money back pretty quickly. PayPal put me through to the Global Shipping contact who helped me through the process.
I think you'll be right 😊
I agree with this. Ebay is collecting extra fees for the Global Shipping service and it is up to them to sort out a lost package. There is very little work required on this to sort it out for either you or the seller. You did the right thing by letting the seller know. He advised you to check the tracking in Australia and when that did not come up that you should file a claim. It is that simple and should not require hours on the phone.
I would not leave any kind of negative or neutral feedback for this transaction.
Also, the package could still be on its way to you. While three weeks is longer than normal, sometimes packages do get hung up somewhere and do not get properly tracked. But one way or the other you will get your item or all your money back.