you can report te problem and you will get an apple credit for unauthorized in-app purchases less than $30 Google in app lawsuit.
But be careful, I made a claim with a handful of examples, and then they agreed to a refund and when I protested with twice as many more, they state that they only make one refund.
My son racked up over $300 before I caught on and they gave a refund of only $175.
In app purchases cannot be unauthorized. In apps can only be purchased from within the app on the device itself, so it is likley that someone you know made the purchase. I'd check with anyone who may have had access to your device before reporting it as unauthorized. I'd also set restrictions on your device(s) so no other in app purchases can be made. This article will show you how to set restrictions on your device: