How to dispute charges by itunes

Obviously nobody on here can potentially refund you, you already know that we are just fellow users and that these are user forums, not iTunes Support nor Apple.

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 it shows there but you didn't buy it, and if nobody else has access to the account and did it, 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 http://www.apple.com/support/itunes/ww or https://www.apple.com/emea/support/itunes/contact.html

If it doesn’t show on your account(s) (and if it isn’t : About payment card authorization holds in the iTunes Store - Apple Support) contact the card issuer

You do not say where you see this purchase. If it is an e-mail are you sure it is real and not an attempt to steal your private information ('phishing') (very common)?

Phishing & Other Suspicious Emails - https://www.apple.com/legal/more-resources/phishing/

Identifying legitimate emails from the iTunes Store - http://support.apple.com/kb/HT2075 (the previous link is more specific)

Forward attempts to: reportphishing@apple.com

If you still think the charge is real:

See your purchase history in the iTunes Store on a Mac or PC - http://support.apple.com/HT204088 - Does not include purchases made by others under Family Sharing; those have to be checked from their accounts.

If you see ‘itunes.com/bill‘ or an unfamiliar charge on your bank, credit card, or debit statement - https://support.apple.com/HT201382 - "Before you contact Apple to request a refund for a charge you don't recognize"...

If neither you nor a family member (if applicable) has a record of this purchase and you only saw it on a statement for a card you alone control, contact your bank or card company about card fraud. Apple does not handle that.

If you now recognize this purchase and are asking for a refund then realize Apple's terms of purchase in the USA are, "All Transactions are final" (https://www.apple.com/legal/internet-services/itunes/us/terms.html), but some countries have different laws so check terms for your country at: http://www.apple.com/legal/internet-services/itunes/. If sales are final then it is Apple's decision if they want to grant a refund. You can always ask, and people do get refunds on a case by case basis, but Apple can also say no.

Get help with an item purchased from the App Store, iTunes Store, or iBooks Store - https://support.apple.com/HT204084

Report a Problem - http://reportaproblem.apple.com - "Sign In for help with iTunes purchases made in the last 90 days"

Other ways to contact iTunes Support:

https://support.apple.com/contact

https://www.apple.com/emea/support/itunes/contact.html

Note, if you get your bank to block a payment to Apple and it is a valid purchase on record it may end up with your account being disabled. Make sure it really is card fraud before you do tell your bank to stop the payment.