If you would have explained what your "notification problem" is would make helping you easier.
So I only can give you a general answer.
If you install WhatsApp on your phone and enable notifications and then go SETTINGS > notifications+actions you will not see WhatsApp.
You only will see it if you got some WhatsApp messages.
Furthermore check the settings in Data Sense and Battery save be sure you do not block something.
If you need more help please register and reply on this post.