I had one (on behalf of my seller friend).
Items purchased, paid for and sent all within 48 hours.
Delivery address about 7km away, as the crow files.
About two weeks later, the buyer contacts my seller friend inquiring about their purchase, as it hadn't arrived. My friend checked the tracking for the registered item - but it was no record was found. (This was not uncommon - as registered items consistently did NOT show up until they actually arrived at the delivery centre. Note - current Australia Post practice is that domestic registered items are scanned on lodgement - if you put them across the counter at a post office. You will then have a tracking event available within half an hour - from my experience.)
The seller apologised for the delay (even though it wasn't their fault) and organised to re-send the items... via pony express (me).
I drove over the next day with the items and knocked on the door at the appointed time. A lovely lady answered the door with some news .... the postie had delivered the missing package about an hour earlier. Apparently the postmark was very clear, so she knew it had been posted quite promptly.
She apologised to me for having made the trip, but I said that was OK - the important thing is that things were sorted out.
I am certain she appreciated the no-fuss service - since she has been back to buy more.