I'm surprised to see that all of the comments say PayPal never rules in the buyer's favour when I have had the opposite experience for years.
In PayPal's Seller Protection Policy it says you are not covered if "You sell services, intangible items, or digital goods." If the seller can not confirm shipping the item with a signature as proof of delivery, PayPal will rule or side with the buyer in most cases.
As with eBay, PayPal seems to have a policy that the buyer is always right. As a seller who works with other sellers of digital items, we complain amongst ourselves about bogus chargebacks by buyers all the time.
Since PayPal requires the seller to "provide either Proof of Shipment or Proof of Delivery to get coverage", in my/our experience, the seller is usually the loser in the case of disputed delivery/receiving of e-goods. And no, PayPal will not accept emails as proof because they have told us they can be easily forged.
I'd simply file a chargeback through PayPal for an item not received. In my experience, you are not the one with the burden of proof.