Morning Lamp (by HarvezApps) lets you delete your account and everything linked to it at any time.
If you can't use the app, email morninglamp.app@gmail.com with the subject “Delete my data”. Because accounts are anonymous (we never ask for your name or email), the in-app option is the only way we can be certain which data is yours, so we'll walk you through it. We reply within 7 days.
Everything is deleted permanently from our servers and from your phone. We do not keep a copy.