I find the postal system charming. It does work, with a little help. In early February, I ordered 3 paperback books from Amazon.com as a test of the system. Call me foolish, but the books cost around $50 USD and I paid $60 for expedited shipping.
Amazon.com said that one of the books would arrive around Feb.11 and the other two, Feb, 15. I stopped in the Sosua post office on Feb. 16. The woman working there said that the packages would be delivered to the guard gate of Perla Marina. But- she then put in front of me a large pile of letters (even though I insisted that my package would not be in letter form.....) The letters dated back to before Christmas! Many were Christmas cards, a few looked like bills.
Here I am going through everyone's mail! This would NEVER happen where I come from!
Anyway, she told me to come back next week and check again.
Two weeks after my given delivery date, I returned. Same scenario....she gave me the pile of mail and said that the package would come to my guard gate. But, then she went in the back and miraculously returned with the second book shipped!
Some archaic paperwork took place where I had to sign my life away that I really did receive the book. Then, I explained that there must be another package, as what she gave me was to arrive after the other one.
No, it is not here, she said. I was to return next week.
Yesterday was the third week after my delivery date. I went back to the PO, had the same conversations, looked through the same stack of Christmas cards and bills. Felt sorry for the individuals who never knew that their loved ones wished them Merry Christmas. Hoped that the people who never received their bill have not been taken to court by now.....Had another thought that maybe some of these envelopes contained checks....money never received!!!!
And, no, my second (actually, first) package had still not arrived. Then, the lady did something different. She asked for my phone number. I explained that my Spanish is good enough to speak to her in person, but if she calls me, I won't understand what she is saying. She replied that she would say hello, then say "Sosua Post Office." I would understand. And then, I should come there.
Well, Glory to God, it worked. She called late in the afternoon. My books are at the post office, and today I will pick them up.
To answer the OP's question, that is how the Post Office works.