OP, I have currently a similar situation. Charge back for unauthorised credit card use, paypal has held the funds for a couple of weeks now. I have uploaded tracking advise. I tried calling the buyer, to find that the number was disconnected. I don't think there is anything more to do but wait for paypal to decide.

If you have signature tracking proof of delivery, paypal should cover you with seller protection. But it can take a while for it to be decided.