Account fraud??

Has anyone had a fraudulent purchase happen on their account? I have my settings for a Pin to be required for purchase, yet somehow someone rented a movie and is watching it on a device that I can't find.

Fandango isn't refunding me, even though I called before the movie was watched and told them I didn't buy it.

I have a sibling who does have access to my account but they are at work and have been since this movie was initially rented so it's not him. Plus it's a kids movie. Which seems odd.