Impotent rage at USPS

There was a three week period where I was abroad but no one was here to check the mail. I just found out that (becuase my subletters or the neighborhood kids removed my name from the mailbox) that the substitute carrier (not even my usual incompetent carrier) has returned all my mail to sender from that period. It took one post office visit, three calls, and a supervisor discussion to get this information, which is not even certain - just a best guess. The reason given was that Cambridge has a rule that the name must be on the box due to the high turnover rate. This is obviously not a universal rule, as I can remember receiving mail for years in boxes with no name in Texas.
(And if that's the rule, why do I still get mail for previous occupants?) Final paystub, required for financial aid purposes: lost. The firm gave me a screenshot of their payroll system. Maybe that will work.

Augh.