Notification alert sound is not functioning!

I have a problem regarding alert tones like messages, whatsapp, wechat but my ringtones and alarm perfectly working. It put me to the dead end after i try to check my mode ringtones bot in silent mode, check the sound setting, the silent lever on the left side upper part of the device, do not disturb mode and switch off the phone but nothing seems work! I am using iphone 5s and updated IOS 8.3 . Anyone that could help me in this matter?