Do you think the USPS will actually issue a refund for this?

I recently shipped some very large boxes from Chicago to NYC. I went to the local NYC post office to pick them up (as they were unsuccessful getting me at home). I got a bunch of packages and asked, “hey, are there any more?” because I suspected there were (yes I know I should have counted how many I had shipped, but its a moot point). They said “nope, that’s it.” Turns out they were wrong, shipped it back to Chicago, and now I had to pay for shipping, AGAIN, to get it back to NYC.

They screwed up, and I want my $ back. Thoughts? Methods to get this done?

Thx for the help Flutherians.