Big Notifications not working

I am trying to use the expanded notifications but they seem to be not working,

Here is my code

        var notificationBuilder = new NotificationCompat.Builder(this)
            .SetSmallIcon(Resource.Drawable.icon)
            .SetContentTitle(title)
            .SetContentText(text)
            .SetAutoCancel(true)
            .SetSound(RingtoneManager.GetDefaultUri(RingtoneType.Notification))
            .SetStyle(new NotificationCompat.BigTextStyle().BigText(text))
            .SetContentIntent(pendingIntent);

        var notificationManager = (NotificationManager)GetSystemService(NotificationService);
        notificationManager.Notify(id++, notificationBuilder.Build());

Am I missing something ?