You need to find your original sales invoice (from email or order history) and send it to the courier. Reply to the suspension message with the invoice attached as a PDF, or upload it through the tracking link if available. If you don’t have the invoice, contact the seller to provide one. You need to contact the receiver to cooperate with you to submit in China. 

 

Read more: https://www.chinapostaltracking.com/faq/returned-package-lack-invoice/