Hello, when I receive a text on my HTC ONE M9, the notification sounds every 15 seconds until I attend to the text. I only need it to sound once or twice at the most. I have unchecked every option in Sound and Notification but it continue to sound (Lilac) every 15 or so seconds. Surely, this is part of the phone's sounds and not anything to do with my email account as I have read in earlier posts. They are two(2) separate operations in my world. How do I get a one-time text sound when a text comes in? Thank you for all your great info here! 