no signature, basic tracking information confirming delivery to their suburb, and the date...

When tracking says that the item has been delivered to their suburb, it can still be sitting in the postal delivery room for up to another 7 days before actually being delivered to the intended recipient. (slack isnt it!!)

Tell your buyer that the item has arrived to his suburb (town) but will now depend on the delivery times at his end. He should make enquiries at the postal service his end and mention the tracking number when doing it.

Dont panic just yet.

If he opens an Item not received case against you, then come back here for further advice 🙂