To cancel a subscription, go through the settings of the app store. Deleting the app does not stop the payment.
On iPhone:
Open Settings.
Tap your name, then Subscriptions.
Tap the subscription, then Cancel Subscription. You should see « Expires on » followed by a date.
On Android:
Open Google Play.
Tap your profile picture > Payments and subscriptions > Subscriptions.
Tap the subscription, then Cancel subscription. You should see the date your access ends.
If you don’t see it: the subscription may have been taken out on the app’s website. Sign in on that site, then look for « Account » or « Billing ».
Limitation: cancelling stops the next payment, not the one already made. Your access stays open until the end of the period you paid for.
To picture it: uninstalling the app without cancelling is like throwing out a magazine without ending the subscription: it keeps arriving, and keeps being billed.
Trusted links: Cancel an Apple subscription · Cancel a Google Play subscription