I'm looking to sell some concert tickets on ebay and they are e tickets. The payment method I will be using is Paypal, if a situation where the buyer pays for the tickets through paypal, I send the tickets, the buyer goes to the concert and files a chargeback dispute. What do I need to do to prove that I did send the tickets? This is my first time using ebay for this and im very scared as there have been stories of this happening.