Canceled my Apple Music subscription & I am still being charged

First confirm it’s been cancelled and while in your subscriptions, have a look if there’s any apps charging you.

• For help with recurring charges, you can view, change, or cancel your subscriptions

and check your purchase history to see exactly what the charges were for. It will say “Apple Music Membership” if it’s for that.

if you still feel this is in error:

Request a refund for an App Store or iTunes Store purchase

https://support.apple.com/en-ca/HT204084