Hi Violetrose and welcome. Don't worry you have not thrown away $84. Help is at hand (if not from me, from another member). Now I'm trying to remember my process when buying ARV from the Microsoft Store. Firstly you don't see it in your list of programmes?

I tried this just now - go to the Microsoft Store, search for the app ArtRageVitae - as you have already brought this as I have, you should be presented with page which tells you that you own this app and offers to install or open. You can open from here and once open pin to your task bar. You shouldn't have to jump thru these hoops but if it is not showing on your computer this is one way of doing it.

You might get other suggestions as others read your post.