i am being charged for an app that i did not purchase. Who do I report it to?

Follow the steps in the support document you posted from, to cancel it. If the app is not showing up as a subscription when following those steps, then how do you know you are being charged for it exactly?

You can contact Apple Support directly by using the link in the support document you came from.

If you got an email for a charge, make sure its really from Apple, and that you were actually charged, in most cases emails that say you were charged are just scams.

See here: link-> Identify legitimate emails from the App Store or iTunes Store - Apple Support