Usually, you need to open a case for each item (it's counter-intuitive in some ways, but eBay set it up that way so people could open cases about one item in an order rather than the whole lot, where it's more appropriate).

Don't forget postage in qld and nsw is at a standstill due to floods.

All parcels unless express ones travel by road and Aus post is not allowed to travel in many places. International mail comes into Sydney then by road so if you're in northern nsw or qld I was told up to 2 weeks delay when I posted something today.

If it was ebay's estimated arrival date then you should give it at least another five to ten business days for a realistic time of delivery plus of course any impact the flooding may have. Does the parcel have tracking and if so what does that say?