NOT HAPPY WITH APP OR $19.99 CHARGE

Just deleting an app won't stop a subscription, if you no longer want the subscription and if you haven't already done so you should stop its auto-renewal : View, change, or cancel your subscriptions - Apple Support

In terms of a refund purchases are considered final, 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

The billing of purchased apps or app subscriptions does not depend on your satisfaction with the app.

The deletion of an app does not undo its purchase, in-app purchases, or cancel its subscription.

To end your subscription, you will have to cancel it yourself. It has to be your action.

View, change, or cancel your subscriptions - Apple Support

Apple does realize that some users can make accidental and unintended purchases at first. Use the ‘report a problem’-link in the invoice email for that purchase, to get in touch with the Support team and make your request.