my Dad(35 yr veteran mail carrier) says to call the Post Office at 8 in the morning, ask for the Carrier Supervisor, explain the situation and ask to talk to the carrier on your route. They will still be in the building at that time of day. And if you call the 800 number they will investigate it for you but, you would probably do best to try to catch the carrier before they have left for the route first. Good luck.