Monthly Music Purchase $9.99

Purchases are considered final but you could try the 'report a problem' page to contact iTunes Support and see if they will refund or credit you as a one-off : http://reportaproblem.apple.com

Or you can try contacting iTunes Support via : https://support.apple.com/contact or https://www.apple.com/emea/support/itunes/contact.html

Manage your Apple Music membership - Apple Support - https://support.apple.com/HT204939 - "Learn how to change from an Individual membership to a Family membership, turn off automatic renewal, or join Apple Music later." Turn off autorenewal and your membership will finish at the end of the current subscription period.

Report a Problem - http://reportaproblem.apple.com - "Sign In for help with iTunes purchases made in the last 90 days"

iTunes [Store] Support - Use this form for assistance with account and billing, code redemption, or purchase questions - https://ssl.apple.com/emea/support/itunes/contact.html