Is it indoors?

It was outdoors (with the same problem), but I brought it indoors about a week ago and placed near my south facing window.

It will be happier outside. It is likely to be even more problematical inside. Since it is going into winter it should be expected to die back. Does it get enough water?

OK, I will return it to the balcony.

It was growing in a garden soil before (in a pot), but I replanted it and now I use mixture of coco coir, vermicompost and perlite, which holds water very well. I see that the plant started to grow better, there are a few new stems. But the replanting didn't solve the problem with leaves.

Roots are not yet established! Nor are they getting a chance to do so.