I said 'what don't you know' to a customer asking for a cigarette I'd never heard of

so there's this cigarette brand called something like "Dis Africa" or whatever. I literally just started working at a convenience store like two weeks ago so I don't know half the cigarette names yet. anyway there's a line of customers and I'm ringing people up and suddenly this customer goes "I don't know." and I'm like "what? what don't you know?" thinking they're confused about something. TURNS OUT they were asking for a cigarette called "I Don't Know" (or whatever the actual name is) and I just made them repeat it three times in front of everyone. I wanted to DIE. the shame. LMAOOOOO I'm still thinking about it.