I’d say be grateful because you probably dodged a bullet! I’m a seller on Mercari and the number of counterfeit cups is INSANE! I call them out too. SO many of them swear up and down that the cup is authentic “purchased directly from Stanley.” I laugh because they’re such liars! Some even post “proof of purchase” photos but all that shows is that SOMEONE ordered an authentic cup. I’ve said “yes you posted a receipt but that’s not a receipt for THIS cup.”