How do I get a refund and unsubscribe?

To unsubscribe : View, change, or cancel your subscriptions - Apple Support

For a refund purchases are considered final as you know, but you could try the 'report a problem' page to contact iTunes Support and see if they will refund you as a one-off : http://reportaproblem.apple.com

Or you can try contacting iTunes Support via : 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 ‘Get support’)