If the international express has been sent and you haven't received it, it is detained by the domestic customs. Because you buy things in Amazon, Japan, Japanese merchants are only responsible for express delivery to you, and will not help you with tax returns. If the value of your purchases is too high, China Customs will detain them. You'd better check the express number and see if it's left at the customs. If you don't handle the courier for 30 days, it will be gone ~ (in fact, the unclaimed handling method for 30 days is likely to be embezzled by the staff)