It's pretty sad to hear when a collectible doesn't reach the destination. And at the same time, I am little afraid as well while shipping some expensive items. Until the package reaches my destination, it would be a kind of nightmare for me and the same would be for anyone who is experiencing a situation like me. My experience as a collector (less than 10 trades) was good to be honest but nowadays I am kind of afraid to buy little expensive items from far off countries. I am very much sure my country is bad in handling international goods, it can go wrong anytime and well that's one major problem associated with shipping items to my country.
All I can suggest you is to wait for the package to arrive for a little more time as I had a silver bitcoin collectible item stuck in customs for over 1 month when it was shipped from USA. Another negative aspect is that my country imposes around 50% of customs duty which is damn high. If they don't return up for a month, start enquiring about the package in nearest post office? I think it might be of some help, but not really sure about this!
To prevent such bizarre nightmares and problematic situations in future, you could try to follow 2 things in your future buys.
1. Shifting most of your future buys to a fellow country collector. Shipping within the same territory is always much safer as you don't need to undergo any customs charges and other problematic stuffs. If you are worried you can travel to the destination and get that hand-delivered.
2. If you don't have a fellow country physical bitcoin collector, talk to any of your friend who is living in USA or the country where the collectible is located. Ask them to receive it on behalf of you and you can very well get that from him when you guys have a friendly meet-up.
P.S I have already followed both the above mentioned ideas and now my coins is in the home safely!