do you open a case through ebay or paypal for item not received?

1976ToppsCollector

i bought a pre-sale case of alvin & ginter, and i am certain that the seller is giving me the runaround on why he hasnt shipped it yet. i am giving him one more chance to respond to a message before i open a case againt him. which is better, to do it through ebay or paypals?

charrigan

Either works but I use eBay. Very easy.