not sure about the chargeback stuff, but my recent experience with paypal went like this
he filled in dispute form saying "email sent" that's all it said
I get an email alerting me to the fact a dispute had been filed and to put my side
I send a detailed reply of everything that had happened from time of sending, down to where package was in use, and detailed whois records to show it was the buyer useing it.
he doesn't reply and after 20 odd days it went to paypal to be reviewed
he was awarded the refund and i got a message telling me i wasn't covered by the seller protection