iTunes charge

If you cancelled it at least 24 hours prior to its renewal date : http://reportaproblem.apple.com or http://www.apple.com/support/itunes/ww (click on your country's flag, the country where you live, and which is therefore the country on the account ; click on Contact Support towards the top right ; click on Get Help under 'Talk To Us’)

Look at the purchase histories of all iTunes accounts you have linked to the card : See your purchase history in the App Store or iTunes Store - Apple Support