Hi jebcat
Did you get a message like this one?

If you did it and click on the "reward" link, it will take you to your Achievements page.
(this is also accessible via MY LADY > ACHIEVEMENTS)

You've got 6 different areas where you can win rewards.

Just click on them all to open the page, if you have completed an achievement and haven't collected the reward yet, it will show a little gift icon. Once you've collected the reward, it change to a tick. Achievements that haven't been completed yet will have nothing.

Remember that should you have received a reward, your message will remain in the NOTIFICATIONS section 'till you delete it.
Hugs
Red