How to cancel FireApps subscription
A FireApps subscription gets canceled once you uninstall the app through Shopify or close down your e-store. You can remove an app from your Shopify store through your Shopify admin > Apps page. Locate the app you want to uninstall, and click the garbage can to delete the App.
Note: Unless you close down your store, Shopify will still charge you after 30 days installing paid plan, even you've already uninstalled the app.