Have you looked at the purchase histories of all iTunes accounts linked to the card : See your purchase history in the iTunes Store on a Mac or PC - Apple Support ?
If they show there but you didn't buy them, and if nobody else has access to the account and did them, change the account's password if you haven't already done so (What to do after you change your Apple ID email address or password - Apple Support) and contact iTunes Support : http://reportaproblem.apple.com or https://www.apple.com/emea/support/itunes/contact.html
If they doesn’t show on your account(s) (and if they aren't : About payment card authorization holds in the iTunes Store - Apple Support) contact the card issuer