Go physically in and ask for Post Master....had same issue....it worked...
It probably fell open after he shut it and pulled away. Also was it shut when they put the mail in.
It's easiest just to stop into your local post office and speak with the postmaster.
The physical number to the post office usually posted in the next section after the google listing with the 1800 number.
Call the number listen to the options n itll get y6oy to someone who can give you your post offices actual number
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