Why they're charge me for Pandora

If the only indication of the Pandora 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. 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

You can use the following instructions to determine if it is a real charge, what it is for, and to report a problem: Get help with an item purchased from the App Store, iTunes Store, or iBooks Store - Apple Support

If the charge is for a Pandora subscription you can use the following instructions to cancel: View, change, or cancel your subscriptions - Apple Support

Also see: If you see 'itunes.com/bill' or an unfamiliar charge on your statement - Apple Support

Obviously nobody on here will know what has or hasn't on your account, and nobody has been taking any money from you. If you've looked at the account's purchase history and can't see where the money went (the purchase history on a computer's iTunes shows how each item paid for) have you contacted iTunes Support ?