If you are on a trial and would like to stop receiving emails from Sonix, you can delete your account by clicking "Delete Account".
"Delete Account" can be found in your account menu. Click your name in the top right hand corner and "Delete Account will be in the right navigation.
If you are subscribed to Sonix and you'd like to delete your account, you'll need to cancel your subscription first. This help article will guide you through that: How do I cancel my subscription?