Mail is considered undeliverable if: 

• The item doesn't display a complete and valid address 
• The item is addressed to a non-existent address 
• The addressee has moved without giving a Mail Forwarding request or the request has expired 
• The addressee refuses the item, the item bears a return address, and the sender refuses it 
• The addressee refuses to pay postage due charges 
• The item is prohibited by law 
• We find the item loose in the mail 
• The item is an empty wrapper or carton 
• We can't otherwise deliver the item to the address 

If you’re a contract customer, you must consult your customer guide to get detailed information on when we'll treat mail as undeliverable for a particular service.