This is Rae from the Shopify team. I appreciate you reaching out about this.
To confirm, is this the app you're using? If so, if you're the store owner of your Shopify account, then you should be able to log in to your admin, click on 'Apps' in the left hand sidebar, and then click the 'Delete' button beside this app to remove it from your admin. Check out this help document for more information on this.
If you're the store owner, but you don't see the 'Delete' button when following the steps above, I suggest clearing your browser cache or using Chrome Incognito mode to try and remove this app instead.
However, if you're still not able to remove this, then I recommend reaching out to the developers who built this app directly. Since they created this app, and fully support it, they're the best people to help advise on how to get it removed from your Shopify admin and stop the charges on your account. You can contact these developers by following these steps.
Please keep me posted on how this goes!
I wanted to follow up with you here to see if you were able to remove this app from your Shopify store?
Let me know if you're still running into troubles, and I'll be happy to lend a hand.