That is how the chargeback process works. The issuer (PayPal) seeks the input of the merchant, the merchant replies, and that is the end of it. Either you receive the credit or you do not. It you wish to "appeal" that determination, you must reach out to PayPal.

Not to be critical, but I would suggest recontacting PayPal and providing a more precise but much shorter explanation than you have done here. While I think that I understand what happened,it is not really clear and if I were an agent processing your claim, I would be hard-pressed.