Just my luck I guess, first time buying costume slots and they only show up on 2 of my 6 captains. For all I know, I might have even bought it twice and it only showed up once for each of those two captains. Once bitten, twice shy, no more appearance purchases for me, ever.
I lodged a ticket # 1601243, but as it's only 250 or 500 zen, I'm not expecting anything. Other players have missing captains, so there's bigger fish to fry.
support.perfectworld.com doesn't seem to show any tickets... so I'm probably doing that wrong too. I hope that was the right way to check the ticket history... in-game help texts are so untrustworthy.