"I'm totally confuse why my plants have lost vigour??"
You have water well, sunlight ok and provided good soil too
But it seem like there is still something wrong with your Ficus Pumila 'White Sunny'
We think its due to it has probably outgrown its pot
This quick-growing plant usually need annual repotting, by increasing the pot size every year
Try today and observe if there is a positive difference on it
Get the plant today from http://GardenMart4u.com