receipt

You are sure that it was a genuine email from Apple and not a phishing attempt trying to get your account and payment details ?

Phishing and similar emails : Phishing & Other Suspicious Emails

Phishing emails : Identifying fraudulent "phishing" email - Apple Support

Genuine iTunes emails : Identifying legitimate emails from the iTunes Store - Apple Support

Viewing your account's purchase history : See your purchase history in the iTunes Store - Apple Support (on an iOS device you can view the last 90 days purchases via http://reportaproblem.apple.com)

If it's a genuine email and it shows on your account's purchase history, and nobody else has access to your account or devices/computers, then contact iTunes Support : https://support.apple.com/contact . And change your account's password http://appleid.apple.com - after changing it : What to do after you change your Apple ID email address or password - Apple Support.

If it is a phishing email you could forward it to Apple : reportphishing@apple.com , and then delete it.

If it's a phishing attempt and you clicked on the link in the email and entered your account id and password then change your password immediately

That isn't an Apple site. The links in my above reply tell you how to identify a phishing or genuine email.