Just show them all the proof you have about the service and send them the logs of your convo, where the provider threatened you, i'm pretty sure, it won't look good for the provider. If you paid with PayPal using your bank account, your only chance is PayPal, because you can't do a chargeback via credit card.
You'll hear and read conflicting things, because every case is different (at least slightly). PayPal isn't a court, where they need to follow precedents. Sometimes they decide this way, other times they decide that way. Hopefully they will decide in your favor this time around. You can't do anything else than submitting all the proofs you have against the seller and hoping for the best.
If the service wasn't as described, on top of that the seller threatened you and you have proof all of this, i don't see why you couldn't win this case.