I had gotten quite a few items from the Cash Shop chance(like the Gifts of Fashion Past, and such). However, after getting annoyed with the pop up enough, I clicked the little box that says not to show it again. After I did that, I haven't been able to purchase any Chance items(I tried a couple different ones, a couple different times). I cleared my cookies, logged back in, and it's still not allowing me to purchase any chance items from the cash shop.

EDIT: I went home and tried on my home computer and it was working fine. I'll see what happens on my work computer next time I go into work again.