Q: purchases not mine

If these charges are being made to a credit card, the most immediate thing you need to do is to call your credit card company and report the unauthorized charges. Your card company can contact Apple if they need additional information.

Next, log into your iTunes Store account and see if the purchases are reflected in the Purchase History. If they are, immediately change the password to your iTunes Store account, making sure it's not something easily guessed or looked up. Then go here:

http://www.apple.com/support/itunes/contact/

and follow the instructions to report the issue to the iTunes Store. 

If the charges are not reflected in the Purchase History, then it's most likely a fraudulent charge to your credit card directly rather than an unauthorized purchase through your iTunes Store account in which case it will be up to your bank to handle.

Regards.

Hi...

See an unfamiliar iTunes Store or App Store charge? Before you contact Apple, check your iTunes Store purchase history for more details please read this article >  iTunes Store charges on credit and debit card statements - Apple Support