I bought an app through the App Store, signed up and subscribed to it and found its not real, is there anyway I can stop the payment?

Apps may or may not meet your expectations, but all apps in the App Store are reviewed and as such they will be real. In-app subscriptions often start with a trial period. Use this period to examine if it meets your expectations, so that you can cancel in time if it doesn’t. Be wary of apps that offer subscriptions without trial period.

If you do not want the subscription, then the first thing to do is to cancel the subscription. View, change, or cancel your subscriptions - Apple Support

apart from talking to your bank then Get help with an item purchased from the App Store, iTunes Store, or iBooks Store - Apple Support