I think you keep your bonsai inside? or am I wrong.
For start, put it outside. Bonsai aren't meant to be inside, most of them will dy because of the dry air inside. It need's to be warm and moist.
The soil of your tree is also bad, water it through so that everything is wet and then only water it after it has slightly dryed up each time.
You can also put the tree with the pot under water and leave it there for 15 minutes, then take it out an the soil will be totaly wet. (Only the pot with the soil under water, not the tree itself)
There is no air or drainage in this kind of soil.
Try this first and see what happens.
kind regards, Luc.