Ficus microcarpa 'Green Island'

So this is actually a Ficus moclame (but I couldn’t find it in the encyclopaedia and don’t have enough knowledge to add it myself) and when I got it the tree was plush and leaves full. However, I’ve had a LOT of leaf drop of over the last few months. At first I thought I was overwatering it, as I had yellow leaves dropping, so I let it dry out, but then dead leaves seemed to replace the overwatered ones and I can’t seem to find a balance... any suggestions?