AusPost aren't the sharpest. I had a mail redirection in place while i was travelling. I sent a bunch of items home. Everything good. Months later I let the redirection expire. Suddenly 90% of my mail failed. I contacted a bunch of senders who said my address was invalid. At the time I didn't make the connection between the mail redirection and delivery problems.
I logged a ticket with AusPost. They couldn't figure out the problem. I still lost mail. They said some guy had gone on holiday. This issue went on for months. I logged another ticket. This was suburban Melbourne not some remote town with a auspost agency only contactable by llamas by the light of the full moon.
No better response. Both tickets auto-closed with no actual resolution. All the while some letters/packages got through and others didn't. A bunch of online sellers had to resend my stuff to an alternate address because the relevant portion of AusPost for my address were too stupid to sort this out. Every courier not connected to AusPost delivered perfectly.
Then all of a sudden around a year later my problems disappeared.
Moral of story: something fishy was going on. Auspost can't debug their own redirections. Delivery problems can really mess up your reputation. Get some kind of workaround from your side operational ASAP.
Yes I had a lock on my letterbox. Yes I was home when packages were delivered. It got so hilarious we'd sit with laptop on front porch. The guy would turn up with the "You weren't home card" then would have to go get the package out of his van.