If you purchased your Headspace subscription through the mobile app via Google Play, you will need to contact Google Play Support in order to get a potential refund.
You can contact Google Play Support at https://support.google.com/googleplay/gethelp
In the meantime, please follow the steps below on your Android device to disable the auto-renew feature for your Headspace subscription:
- Open the Google Play Store app
- Tap Menu
- Tap "Account" and then "Subscriptions"
- Tap the Headspace app
- Tap "Manage", then "Cancel Subscription" and confirm cancellation