I think you should also still be able to appeal PayPal's decision.

That's what an article from last year says:

1. Log into your PayPal account;
2. Select the “Resolution” tab, and choose “Closed Cases” from menu options;
3. Choose the dispute you wish to appeal and click on “Appeal.” The tab will open into a new window with an online appeal form;
4. Enter all the relevant information and submit your form.