Missing Mail is mail that does not arrive at its destination on time. If the mail has been undelivered for 7 days, your customers can begin their search with USPS.
Customers should check the current status of their package, before submitting a search request at MissingMail.USPS.com or before they file a USPS Claim. If insurance was purchased or included with the service selected to ship the package, then file a USPS Insurance Claim after the appropriate timeframe has passed.
For more information, you can:
Visit USPS - Missing Mail.
Visit your local Post Office™ location for assistance in filling out a Missing Mail request.
Call 1-800-275-8777 (1-800-ASK-USPS) to ask for the phone number of your local Consumer Affairs office regarding a Missing Mail request.