Asus101

I may not be telling you the right thing here so I'll tell you things that wont harm the tree any more than already has.

A. take the tree outside. Sad to say its not really enough light inside, even in a window. Many bonsai are sold as an indoor plant but 90% of the time they are wrong. Good ol' sales pitch.

B. The bonsai fertiliser. Its hard to say. I dont think it would have been what the plant needed. I know azalea's need special requirements. Picking up some from your local hardware is all that's needed. Same with the vitamins, the plant may not have needed them. In some cases the wrong fertilizer can kill a tree. Here in Aus i would never dare give my natives plants the same fertilizer, in this case high phosphorus would kill them. But i only learnt that due to some research.

here is some worthwhile reading on azalea's. You should check your labels on the soils and fertilisers and see if anything mentioned in the article matches what you have.