unknown purchase

Unknown Charge

• Curious about a Charge? --> If you see an 'itunes.com/bill' or an unfamiliar charge on your statement
• If you have an issue with an app on App Store or billing --> Request a refund for an App Store or iTunes Store
• You can also request a refund for a recent renewal of an in-app subscription.purchase 

Phishing

• Beware of --> Phishing & Other Suspicious Emails 
• Know how to --> Identify legitimate emails from the App Store or iTunes Store 
• Avoid phishing emails, fake 'virus' alerts, phony support calls, and other scams —> Use these tips to avoid scams and learn what to do if you think your Apple ID has been compromised.

Apple doesn't take money out of any account without your agreement/subscription/purchase/order.

Start here:--> Subscriptions and Billing – Official Apple Support

choosing the section(s) which interest you.

Regards

Giulio