Support
Tell us what happened.
This is a small studio, so there is no ticket queue and no first line. What you write here lands in the inbox of the person who wrote the code. If you would rather use your own email client, write to support@getwhistlestop.app.
If an alarm did not go off, say so first. That is the most serious thing that can go wrong here and it gets looked at before anything else. Include the phone, the version of iOS or Android, whether the phone was locked, and roughly what time it should have fired.
Before you write, two quick things
Battery optimization on Android. Samsung, Xiaomi, OPPO and several others aggressively stop background work, which can delay or silence an alarm from any app including this one. If alarms are late or missing on an Android phone, exempting Whistlestop from battery optimization in the system settings fixes it most of the time.
The preminder is meant to be quiet. By default it is silenced by Focus modes and Do Not Disturb, which is ordinary notification behavior. The alarm itself still comes through. There is a single setting to let preminders through as well, if you would rather.
Everything else is probably answered on how it works or in the questions on the homepage.