I don’t recognize a purchase.

Normally, all sales are considered final, but you can ask for a refund.

If you have received a confirmation email, click the Report a problem link at the bottom.

Purchases problem

If necessary, contact iTunes Support. Either use the form or scroll to the bottom of the page in the 2nd link. Follow through the screens to get a chat or telephone option.  

iTunes Support

iTunes Support – world wide

Go here - If you see apple.com/bill, itunes.com/bill, or an unfamiliar charge on your statement - Apple Support