You should normally hear a short alarm and receive a pop-up message whenever the fasting period starts or ends.
You can modify further settings in the "Me" tab. Please try to switch the notifications on and off there.
Furthermore, notifications are only sent if a fasting week was started. Maybe this has not been the case?
If the issue persists please try the following:
+ It might have to do with old Android versions. Please check, if it is possible to upgrade to a new Android version
+ Check if you have another third party security app installed which might block notifications
+ Check if the power saving mode is activated and switch it off. It sometimes blocks notifications.
+ Go to your systems settings and check if BodyFast has the rights to send notifications (Settings --> Apps --> BodyFast --> notifications)
+ Switch the notifications in the app off and on.
+ Close the app completely and switch your mobile off and on.