To request a refund you must contact Apple directly, as they do not provide us with the ability to process refunds. Only Apple can process refunds for purchases made through an Apple iTunes account. Before you contact Apple please note that they do not normally refund subscriptions unless there is a gross error such as a duplicate or unauthorized purchase.
You can contact Apple Customer Support directly at https://getsupport.apple.com/. When you get to this page, click "Billing & Subscriptions" followed by "Subscriptions & Purchases." Once here, you'll be given a variety of avenues through which you can contact Apple.