I'm sure I've seen it before but I can't for the life of me figure out where to go to see my CSC purchase/spend history. Is that information still available?

go to Items. Under the Cash Shop Items banner, is a shaded banner it will say

You have xxx Cash Shop Credits to spend. An overview of your recent purchases is available here.

Click the here.

Thanks! I feel so dumb, heh.

you are welcome!

Subeta's a pretty complicated place, I can't remember everything and have to ask sometimes too.