I agree regarding the potting of your Dwarf Umbrella Tree (Heptapleurum arboricola 'Variegata')
The container is really pretty but should be used only as a decorative cache pot to hide the plastic nursery pot. Many people don't realize that plants can happily grow and be happy in their original nursery pots for quite some time and will experience stress when the roots are disturbed during repotting.
The stones placed in the bottom of the pot will definitely cause issues and possibly the demise of the plant. It has to do with the water accumulating in the pebbles and soil. When water is unable to drain out of the pot, it settles in the pebbles at the bottom, with the moisture naturally climbing higher into the soil, raising the water table and allowing the soil to become soggy. The wet, soggy soil, depletes the roots of oxygen, causing rot. Even if a pot has drainage holes, it's never a good idea to place stones, pebbles, broken pottery, etc. beneath the soil because it hinders proper drainage.
If at all possible, I'd advise very gently removing the plant from the container without drainage holes and gently sitting it into a pot of the same size that does indeed have holes in the bottom. Give it warmth and bright light and it should recuperate just fine.