Need Help to save my tree

I have this beautiful tree in my house,which makes me think I live on a Tree house, its called the Carambola Tree But now its has got some disease, the fruits are getting spoilt by some white fungus and the tree has some ulcer kind of marks.

If any one you are good at gardening, please me know what needs to be done, I have called a couple of gardeners, but living in Hiranandani Gardens all these gardeners are super busy.Check out the pictures below.