How to cancel the things you brought in a credit card
How to get your money back in your credit card
How to get your money back in your credit card
Purchases are considered final but you could try the 'report a problem' page to contact iTunes Support and see if they will refund or credit you : http://reportaproblem.apple.com
Or you can try contacting iTunes Support via : https://support.apple.com/contact or https://www.apple.com/emea/support/itunes/contact.html
How to cancel the things you brought in a credit card