Let's try a thought experiment:
- I buy a game from you.
- You ship it to me, and for whatever reason I never get it.
- I call my Visa card and tell them, "I was charged $20 for a game I never got."
What do you think will happen next?
Answer:
- Visa reverses the $20 charge.
- Paypal asks seller (you) for proof of delivery.
- You have delivery confirmation, [and the seller typed the DC number into paypal as "proof of shipment"], but because the post office lost it & never delivered the item, the DC shows no record of delivery.
- Paypal sucks $20 out of your account & refunds it back to Visa.
You lost 20 bucks. It doesn't matter if you say, "Not responsible for lost packages." Neither Paypal nor my Visa card will care. It sucks for us sellers, but that's how it works.