The suckage: I mailed my January mortgage check in plenty of time for it to reach my credit union (Digital Federal Credit Union - a carryover from my days at DEC). But 10 days after I mailed it, I get home and look at the mail and find that the USPS had decided to deliver the check to me! The routing code printed on the envelope had been crossed out with a Sharpie, and someone had even written TO: next to the address window (showing the credit union address) on the envelope. By this date, the payment was already overdue.
I called the credit union right away and explained what had happened. The next day my wife took the envelope to the post office and ended up talking with the postmaster. He gave some explanation, and offered to re-send the letter in a USPS envelope (at their expense - such a deal).
A few days later I get a "missed payment" statement for the next month's payment which included somewhere around $48 in late fees.
The NSS: Today I called the credit union, again explained what had happened, and asked if they could verify that they had received the payment (they got it yesterday). I then made some comment that I guess I would be eating the $48 in late fees courtesy of my friendly post office. The guy took some information and said he would take care of removing the charge.