I’m being charged for an subscription I can’t see of haven’t been using

How are you trying to find your subscription?

You can view and cancel your subscription following the steps at How to cancel a subscription from Apple – Apple Support - You should do this to avoid being charged in the future.

You could potentially try and claim a refund by contacting Apple's Form > Request a refund for apps or content that you bought from Apple – Apple Support however this isn't guaranteed and it is up to whether Apple allow the refund or not.