my bonsais are dying.

So I have two bonsais. I got them last year, I take really good care about them, at least I think. But I didn´t know they are so sensitive to everything?? If you want to own them, you have to be patient. Really patient. You need to have the right temperature of room, good lightning and clear water (not tap water) and some tools, maybe more things. I can put them anywhere in my room, have the right temperature and really good water, but they are still dying?? There are not any leaves at all. But I got some recommendation that my grandma has magic flat???? I don´t get it, but my sister told me that when she brough her plants to our grandma, they magically came back to life. Maybe I should try it.
Or maybe take better care of them.