It is a phishing attempt. Do not respond. Do not divulge any personal or financial information. You can use the address below to forward the suspect email message, as an attachment to Apple.
The link below has information to help identify fraudulent emails.
Those emails are unfortunately fairly common phishing attempts 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
You can use the following to determine if it is a real charge, what it is for, and to report a problem: See your purchase history in the iTunes Store on a Mac or PC - Apple Support
e-mail about a fraudulent purchase
