I've had my new a12 beeping (sound notification) beeping every few minutes kept me awake all night. I've tried everything even turning if the NFC but to no avail. But my husband had a look at my phone and I had to turn off "NOTIFICATION REMINDERS' in settings. It was set for 3 minutes. The information is in the 'DO NOT DISTURB' section. I'm hoping this helps other customers with this annoying problem.
