Hey! I'm the one who bought the skins for leveling!
I'll admit, I didn't read the fine print. I played other mmos like FFXIV, WoW, SW:TOR, or other free to play games like Path of Exile, Warframe and many mobas, and in every one of those games, when I bought a skin, I just used it whenever. So I went in the store with that expectation.
Btw I don't even think the system is 100% terrible and should be abolished. I can see how it caters to enfranchised players that have tons of transmutation charges. It's just a system I don't agree with, asking the new player, that barely knows your game, to pay extra to use a skin they already paid for, in a game they just paid to get in, leaves a really bad taste in my mouth.
I got an outfit to fix this problem they designed for me, and I'll keep playing because I already paid for the game, but I don't think I'll use this cash shop ever again.