Is it the Dior perfume from the US? 

If it is, I am very surprised at it being a fake as the seller has no record of selling fakes...all the negs seem to be for slow postage.

Are you allowing for the fact that the packaging can change from country to country.

And the seller has done nothing wrong with the postage.....they do not abide by Australia Posts's rules. 

You will have to get a statement on letterhead paper from an agent or authorised seller of he perfume to state that it is fake.  If you are unable to get that then you are wasting your time opening a dispute with paypal.