You should be able to go into the settings on the app on your phone and check to stop receiving notifications. The app settings is not your phone settings. You will open up the Farm Heroes app and before clicking ok or play you can go into the settings for the app and make that change.
It comes from the app I believe. When I click on it to open I get nothing but a black screen for a few seconds and then it kicks me out back to my mobile home page and error pops up saying "Sorry! The application Farm Heroes Saga (process.com.king.farmheroessaga) has stopped unexpectedly. Please try again." Nothing I try…