Phone PayPal and ask to speak to a supervisor.

Tell the supervisor that they have all the information and they need, and it’s time to reverse their decision.  Also tell them they have 24 hours to do so, or you’ll lodge a dispute with the Financial Ombudsman Service.

My bet is, they’ll cave shortly after the O word is used, and if not, shortly after you actually lodge the complaint, and in any event it’s a free service so you have nothing to lose.

 As for the other sellers, you may want to draw their attention to this thread.