Look like a lack of evidence. you have to take the proof PayPal transaction and anything necessary. Take a look at what happens when a lack of proof? no response by the member and I thing in case the same way. Paypal it could be canceling your case if you don't send any valid proof.
So, it is an auto-buy shop, you don't know there are has products are valid, Seller might be put his shop as though empty product, invalid code, wrong password and etc to tricking free money.
You have read more about dispute
https://www.paypal.com/id/webapps/mpp/buyer-dispute-resolution?locale.x=en_ID and you can see what not covered by PayPal.
What items are not covered under Buyer Protection?real estate
businesses
vehicles
custom made items
and licences
I am not sure, Are you bought licenses product?