I have a chinese elm bonsai, I keep it on the window sill in the kitchen as I was told it was good for them with the humidity. I have had it since december last year. I started to prune it about 4-5 mnths ago following the guidelines. It has now lost all of its leaves, it's still alive as it is very green underneath the bark and it produces leaves sporadically then drops them, then it produces leaves in a different part of the tree, but never fully covering the branches as a whole at the same time.
I have read due to the pruning/over pruning its gone in to shock. It was a beautiful tree when I first received it as a gift full of leaves and healthy looking, I would like to try and get it back to that way, but not sure how, does it need repotting?