PayPal from a Google search - If you refund a payment for goods or services, there are no fees to issue the refund, but the fees you originally paid as the seller are not returned to you. The amount of the refunded payment will be deducted from your PayPal account.

So the seller would need to refund the fee, but may have deducted from the refund to you. Did you see if the seller refunded the total amount paid back to you? Or did they short the refund?

“There is no limit to the amount of good you can do if you don’t care who gets credit.” R. Reagan