There are many reasons why this could be the case, we would recommend checking your courier tracking link.
COLLECTION FROM POST OFFICE
Where a safe place to leave the order could not be identified, the order will may be taken to a Post Office nearby.
To confirm that has occurred, you can review your order using this more detailed tracking link https://startrack.com.au/track/search.
LEFT IN A SAFE PLACE
The courier will not require a signature for delivery, and will typically leave the order in a safe place.
We recommend carefully checking your property for the order.