That's a very visible crease. I doubt they'll take it back.
You could resell it on eBay, as most buyers don't seem terribly concerned with a crease like that, especially since there's no wear on the soles.
I would suggest in the future that when you try shell shoes on, you do not flex the shoe at all, as it will result in a crease. Trying them out on carpet will not make any difference - it's the flexing of the vamp that causes the creasing in every shell shoe.
Edited by JSO1 - 7/11/15 at 7:22pm