Bill payment
On October 12, money was deducted from my bank card for subscribing to an application that I do not have on my device and which I do not use. How to return my money?
Deleting an app only deletes the app, it does not stop a subscription - I assume you've now stopped its auto-renewal if you no longer want it.
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 Contact Support towards the top right ; click on Get Help under 'Talk To Us’)