I can clear this up a little
When we got back from vacation, I had a note in my box saying $0.20 due. I took the slip to the p.o. and they said they had already returned it to you because they only hold them for a few days. So I missed that window due to being on vacation. Bad policy I think because they were holding my mail for me, so they knew I could not get in to the p.o. to pay the postage due . . .
I do think the p.o. is getting worse. More stuff is getting torn and damaged, and sometimes it seems to take forever for things to get delivered.