That really sucks. Have you tried "registered mail" for First Class and Priority overseas? It costs $11-$12 but it does track all the way till delivered. But why was the Express Mail unable to track? It should be though.
Express/ Priority/ Registered Mail were all successful in tracking for our consumers in other countries except China.
We're not sure what was going on but a lot of our packages were being unsuccessfully delivered. Out of 9 large orders we delivered to China, we only received 2 back.
We have developed a more safe system for delivery but for now we will be distributing most of our goods through private vendors in China to help distribute our keycaps safely.
We are not trying to state that all Chinese buyers are bad people in any way. We hope nobody misunderstands this.
If we have offended anybody we'd like to truly apologize for the misunderstanding.