Yes, I do agree that if PP can be appealed, that would be the best outcome.

As I understand it, there was an Ebay case which the buyer lost and you can explain that they opened a case in Paypal which you did not realise and therefore you inadvertently  were not able to provide the necessary information in a timely manner. You can just point out that there was no reason for the buyer to open the PP case other than their desire to gain both the item and a refund.