Questions, problems with the app, billing, or feedback: email hey@lumenbyjonah.com.
In the app: open Settings, tap Delete account, and type DELETE. It happens right away.
Can't sign in, or don't have the app anymore? Email hey@lumenbyjonah.com from the email address on your Lumen account, with the subject "Delete my Lumen account". Jonah deletes it and writes back when it is done. You do not need to give a reason.
Either way, your login and the records saved in your account are deleted, and any Lumen plan you pay for is cancelled first so you are not charged again. A few things stay: files you uploaded are not erased from storage, and Stripe's payment records and squad reports are kept. The privacy policy lists everything that stays.