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/?caller=kbase&PGF=PGF63006&category_id=SC0060&symptom_id=23208 and try to get a live representative,
or,
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