Subscriptions will continue until the expiration date. Canceling them just tells them not to renew after that date. To have it end before that date you need to contact Apple and explain you need it to end immediately.
Click here --> https://getsupport.apple.com/solutions Enter “Cancel subscription” in the search feature, enter, then on the next page scroll down to the chat or phone call option.
or:
Contact Apple for support and service --> "See a list of Apple phone numbers around the world." Click here --> Contact Apple for support and service - Apple Support
How to cancel a subscription on your iPhone or iPad
1. Open the Settings app.
2. Tap your name.
3. Tap Subscriptions.
4. Tap the subscription.
5. Tap Cancel Subscription. You might need to scroll down to find the Cancel Subscription button. If there is no Cancel button or you see an expiration message in red text, the subscription is already canceled.