geofence with notication and event

hello ... i am working on my project using xamarin forms in which if the user enter a specific region a event is trigger with a notification. i dont have any idea how to do it i used shiny.geofence and crossgreek plugins ... the code is running fine in both plugins but i am not getting any notification if the user is enter or exit in region . is anyone know any other plugin through which i can trigger notification and after notification a event?
if anybody have working xamarin forms sample of geofence it will be very helpful .... THANK YOU !!!