Why did you return the goods BEFORE the claim was decided and before paypal gave you the address to return them to (trackable to prove delivery back to the seller)?
All i can suggest is that if you funded your paypal payment via a credit card then contact your card issuer and see if they will chargeback for you.
Advice is voluntary. Kudos / Solution appreciated.
I'm disabled and have never used the dispute/claim process before. I'm in the same situation as the OP. It's very easy to mistake what to do as a scammed buyer, in terms of indicating the item was received or not. What's worse is that you can't get a hold of paypal agents. It's truly insane!
