[z4plin]

I live in a apartment building so they take it to my local Aus post office and I go and collect it

Do they not buzz you on arrival and If you don't answer, a missed delivery note Is left and It's then taken to the post office?

they just take it to my local post office maybe because the assigned mailbox for my address can only fit letters.

Someone at your address may have setup parcel redirection which may explain why they are all automatically going to the post office.
I'd jump in Auspost liveChat and ask them why your parcels are going straight to the post office without you having a chance to collect it from home.