Looking at some of your listings (and how much you are charging for postage) I would suggest that maybe you are not packing adequately. For example you have a creamer & sugar bowl with postage at $11.45. This price would suggest you are planning on a parcel under 500 grams (or a small satchel).

There is no way I would expect to securely pack both items and post at that price (yes I would be able to send one or the other at that price).

No matter which carrier you use your parcels will be thrown around & Australia Post state that they drop parcels from a conveyor belt at a height of 2 metres (and then theoretically may drop parcels up to 20kg on top).

A while ago I posted some parcels at my PO and the contractor arrived at the same time. He proceeded to toss all of the parcels in through the sliding door of the van (with force and at a distance of almost 3 metres). They were literally bouncing off the back wall of the vehicle. If this is how they treat parcels in front of the customer. I hate to think what goes on at the depot (out of view of the public). 

You really need to pack breakable item with these potential scenarios at the back of your mind.

Hopefully you find a solution.