How do I raise refund request for unknown subscription charge linked to my Apple Account?

You won't get an email asking you if you want to be charged for a subscription. Authorization is done by double clicking the side button with the amount showing on the screen, followed by verification with FaceID/TouchID or Passcode. If it is a Free Trial, you will see the expiration date as well as the subscription price if not cancelled at least 24 hours before the trial period ends.

• You can view your subscriptions that you have authorized here:

View or cancel app subscriptions on iPhone - Apple Support

• If you are the Organizer of a family plan, then members can make purchases when using Purchase Sharing.
• While generally all purchases in the App Store are final, you can request a refund here, although it is not guaranteed and not given very often with subscriptions.

Request a refund for apps or content that you bought from Apple - Apple Support