Just send a dispute the product was not recieved. DO NOT say this was a virtual item (Paypal will dismiss the case 100% TOTALLY!, I know this first hand), but rather you purchased the time invested into the account, AND THE physical generation of the registration codes used to own the software. You are not purchasing intellectual rights, your are purchasing software and registration codes generated from the company. File the complaint as tangable goods.
The registrations codes will make this a tangable item, provided you instructed for this information to be sent to your residence. Since this is a story of your side verse the seller, who's the say your in the wrong, or even the seller is in the wrong. Paypal will freeze the funds and refund you if you provide convincing information.
I recently got scammed by a verified paypal seller. Not only did i embarrass this seller, I got this seller to refund my money due to the statements and timestamps of emails sent using the method above. Don't let someone [censored] you over, it's worth fighting for, even if you hold up the funds forever.
There are some really [censored] up people out trying to scam others, I say [censored] those people and fight back against the BS they're dealing.