Hi, akang. I've looked at your pictures. The picture of the plant itself is a little out of focus, but in general it looks ok.
The flowers are dying-- that can happen if the plant is too dry for even a short time. The flowers are sacrificed to spare the plant-- just as in frostbite the body sacrifices a finger or two to save ourselves.
The best advice I can give you is to learn more about phals by reading about them in several different sources.
Here is an url to culture notes from the Canadian Orchid Congress.
The Canadian Orchid Congress
Also check out the culture notes at Big Leaf Orchids (click information tab across the top) and at Bedford Orchids (scroll down to V A and B)