If customer is unavailable upon delivery or if the parcel can't be left at the premises due to risk of theft, AusPost will leave a card with the details of the local Post Office where the parcel will be held for collection. AusPost will not be able to attempt any re-delivery.
If you find customers asking for re-delivery while their order is sitting at the Post Office, you'll need to inform them that AusPost only attempt delivery once and the parcel will need to be collected from the Post Office. You can use the canned response - Attempt Delivery.