Ebays known default position is to side with the buyer. This has come out numerous times, executives and ex employees have said it, theyve said it to the media. Google a little about Ebay.

They do this because there are more sellers than buyers, and they know buyers who have a negative experience (whether they are in the wrong or not), tend not to come back to buy again. Despite listing fees, buyers are what make Ebay money. Not sellers.

This is why they promote buyers consumer rights but have nothing about sellers rights on their site (in Australia, sellers actually have many rights).

This is how Ebay works. I know its frustrating, but signing up to a service, then complaining about their policys is a little pointless.

If Ebay breaks your sellers rights, or makes decsions in support of a buyer against a seller that breaks sellers rights in Australia you can report them to the ACCC, Financial services ombudsman etc. They are quick online forms.  

They do break our rights and make decisions contrary to Australian Consumer law frequently (Ive only been selling three months and theyve sided twice with the buyer when I was in the legal right, Ive also seen many examples on this board). Unfortunately most sellers are too lazy to find out what their rights actually are let alone do anything about it.

The only way it will change is if there are enough complaints to the appropriate Australian departments. Every seller needs to lodge a complaint every single time it happens and pressure them to do something about it.