I have received a receipt for a non purchase
I received a receipt for netflix but have made no purchase. I have changed my password for itunes
It's probably a phishing attempt trying to get your account and payment details, if you still have it you could forward it to Apple : reportphishing@apple.com , and then delete it. ?
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)