USPS says the package is delivered, but I haven't received it!
If you haven't already, please try looking for the package somewhere near your front door or asking your neighbors. Sometimes, postal workers leave packages near doorsteps and not near residential post office boxes. Also, a well-meaning neighbor might have taken your package inside their house for safekeeping or for protection against the rain or other bad weather. We have also seen packages to deliver 1-2 days after it has been marked as delivered.
Contact USPS at 1-800-ASK-USPS or contact your local Post Office directly and explain that you have delivery confirmation, but no package was actually delivered, and ask them to start a tracking investigation to discover the whereabouts of your missing package.
Contact the USPS Track and Confirm customer service office at 1-800-222-1811.