I had the same problem (well similar) and had to google it, which led me to a purchase look up page. It is really stupid that they do not have a purchase history in your account page to easy access for this information.
Here's a link to the page:
https://store.na.square-enix.com/DRHM/st...S&Env=BASE
Here's a link to the page:
https://store.na.square-enix.com/DRHM/st...S&Env=BASE