Deleted the app. Still being charged?
How to cancel a subscription when it's missing from your list: trace the charge to the account or company that bills you.
The app and its payment can live in different places. Check the receipt or billing statement for the company that charges you; uninstalling the app again will not stop renewal.
iPhone or iPad: check your Apple Account
Open Settings, tap your name, then Subscriptions. If the plan is missing, search your email for an Apple receipt or invoice and check which Apple Account paid. If a family member's account is on the receipt, that person needs to cancel. If there is no Apple receipt, check the statement for the company or carrier that bills you.
Android: check Google Play
In Play Store, tap your profile, then Payments & subscriptions and Subscriptions. Make sure you are signed in to the Google Account used for the purchase. If the plan still isn't there, it may use an alternative billing system; check the statement and contact the app developer through its official support page. Uninstalling the app does not stop the subscription.
Neither list shows it?
Search your email for the service name, “receipt” or “invoice,” then match it to the merchant on your statement. Open the service through its known app or website and check Billing or Account settings. For a carrier-billed plan, contact the carrier. If a charge is unexpected, check it through your bank or card issuer's official app or number.
After cancelling, save the confirmation
Keep the confirmation email or screen and note the renewal or end date. Access may continue through time already paid, so that alone does not mean cancellation failed. A refund for an earlier charge is a separate request.
Remember: the app icon is not the billing record. Find who charged you, cancel there, and keep proof.
Billing routes and refund rules vary by provider and country. This guide does not access or change your account.
Sources: Apple Support, cancel a subscription · Google Play Help, cancel a subscription · Google Play Help, alternative billing.