Unable to unsubsribe from unwanted app

Does the app show an expiry date or a next billing date? If an expiry date then it is already cancelled. Bear in mind that “cancelling’ a subscription in the App Store really means setting it not to renew - it remains an active subscription until the end of the last period you paid for.

Yes it is cancelled. Like everything else on the App Store subscription purchases are instant and final. Even if you cancel a subscription on the same day you took it out, that won’t stop the payment for the subscription period you bought - it was yours the moment you bought it. You can request a refund by clicking the “Report a problem” link in the purchase email, but refunds are discretionary.

You’re welcome.