canceling a subscription

Please see the following article. https://support.apple.com/en-us/HT202039

Please keep in mind that once you cancel a subscription, it stays active until the end of the billing cycle.

One way of knowing it is cancelled, when you look at the subscription, you will see "expires on" rather than "next billing date."

You will also notice that the red "cancel subscription" button will have been removed.

I would contact Apple Support, however, this could be a delayed charge if the subscription was unable to take the payment on Feb 28. If you don't see the cancel subscription button there, then it should be canceled. Contact Apple Support to verify this information.