cancel subscription

I’ve been charged for more than a year. And I don’t use the. Is Almost impossible to unsubscribe is very frustrating. When I go to the app the option tu unsubscribe is not there when I go into my iPhone subscriptions acrobat adobe doesn’t even appear on the list. Why? Is it hidden ? Because I still getting charged every month religiously. 
please cancel my subscription immediately and refund me for the months of not use.