i just received a copy of an invoice that is not mine. i need to cancel the payment

You are sure that it’s a genuine email from Apple and and that there has been an actual purchase, and not just a phishing attempt trying to get your account and payment details ?

Phishing and similar emails : Avoid phishing emails, fake 'virus' alerts, phony support calls, and other scams - 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 iTunes account's purchase history, and if nobody else has access to your account and did it, 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's a phishing email you could forward it to Apple : reportphishing@apple.com , and then delete it.