FaceTune keeps trying to take payment

A couple weeks ago I was trialling Facetune, after 2 days I got bored and cancelled the free trial and removed the app from my device. For the last week, I continuously keep getting notifications that Facetune is trying to take $98 out of my account. The app is NOT an active subscription, and it does not appear in inactive subscriptions anymore. I cannot for the life of me work out how to make it stop. I know I cancelled the subscription. How do I stop them trying to take money?