If you don't get it, you need to contact the seller to reflect the problem and get a solution as soon as possible. Only the seller could open a case to China Post to investigate where it was delivered and who signed for it. If the seller doesn't reply you, try to contact your bank or visa company to ask for a charge back. Or, open a dispute from the platform you buy it to get refund in time.
If you don't get it, you need to contact the seller to reflect the problem and get a solution as soon as possible. Only the seller could open a case to China Post to investigate where it was delivered and who signed for it. If the seller doesn't reply you, try to contact your bank or visa company to ask for a charge back. Or, open a dispute from the platform you buy it to get refund in time.