I've never sold anything on this forum, but have sold heaps on another forum.
When I ship something, rather than risk getting into the dilemna of who is responsible for a 'missing' or damaged parcel, I always insist on sending stuff by registered and insured post.
That way, hopefully, monetary loss is eliminated and both sides are (I hope!) left feeling the whole transaction is a lot more secure and less up-in-the-air in case of any damage or loss.
Having said all that, I've never had a problem with any parcels and I use Aus Post all the time. They may take forever, but they have always gotten it there for me
Just my humble 2c