1. Payment error: the payee information filled in by the user is incorrect, or the payee account does not exist, or the remittance amount does not match the actual amount, so China Post will return the remittance to the sender.

2. User's application for refund: After payment, the user finds that the payee's information is wrong or has problems, and can contact the payee to negotiate a refund. The two parties reached a refund agreement, and China Post returned the remittance to the remitter.