Most free trials convert to a paid subscription if the trial is not canceled 24 hours before the trial ends.
If you want to cancel a subscription from Apple - Apple Support
Request a refund for apps or content that you bought from Apple - Apple Support
You usually need to speak to Apple Support to resolve a defaulted payment.
Direct link to Apple ID Support options -
https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0998&symptom_id=20198
World-wide Apple Support -
Contact Apple for support and service - Apple Support
M1 Mac mini, macOS 14.3.1; Watch, series 7 GPS/cellular, watchOS 10.3.1; iPhone 12 Pro, iOS 17.3.1; TV 4th Gen, tvOS 17.3; HomePods, audioOS 17.3 and Airport Express w/ Airplay 2