I was charged twice for a movie on Apple TV

• You can’t have more than one instance to a Buy movie on one Apple ID account.
• You can Rent a movie more than once, if 48 hours have passed between first moments of watching.
• You could rent and then later buy the same movie, to get two charges for the same title.
• In theory, a not-so-careful user could make two purchases on different Apple ID accounts.

Your purchase history would have the details of what has happened with charges for content.

View your purchase history for the App Store, iTunes Store, and other Apple media services - Apple Support

That is a shame.

This is a user to user support forum.

Why are you telling us?