We understand that it was just one postal clerk.
And sometimes even the local Post Master will make a mistake.
But one postal clerk does not speak for the entire USPS, especially if he has made a mistake.
The Post Office does have a national customer service hot line that usually gives correct information that can be used to help correct a Postal employee that makes a mistake.
Just keep saying "customer service" to the computerized prompt that answers the phone and you'll get a live person that will look up the regulations and provide the correct information.
Then the clerk or the Post Master can also call and speak to them to verify the information.
The Post Office gave me such a hard time once that they even called the BATF, but they did end up shipping the package.
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