I've gotten two slips to see her and so far, both the items I've tried to purchase just .. go un-purchased, and the ticket slip thing goes away for the shop. Help?

Have you done an account search for the makeup you tried to buy? There is an add to wardrobe button after you buy - maybe you're double clicking or something, or some other way of activating this button.

If you have and you can't find it, you'll need to submit a ticket.