I’m a merchant and I once won a PayPal chargeback.

I sell a software product. Customer generates a key to unlock the code. Once a key is generated, that key will unlock the product forever; it cannot be revoked, thus no refund at that point.

In the dispute form, I wrote “It’s like buying a DVD from Walmart — once the cellophane is torn open...”

PayPal judged in my favor and refused the chargeback of $349.

I’ve had 2 or 3 chargebacks from Visa and never won those.