I'm been charged for something I don't have a clue

See: Request a refund for an App Store or iTunes Store purchase - Apple Support

Also, if the only indication of the charges is from an email or text, be aware that it may be a phishing attempt to get you to log in to a site that appears to be Apple and divulge your password or credit card information. See: Avoid phishing emails, fake 'virus' alerts, phony support calls, and other scams - Apple Support

and Identify legitimate emails from the App Store or iTunes Store - Apple Support