Lipstick plants like bright light, you might want to investigate extra indoor lighting for plants. Now, if your plant has lost all its leaves, it could be from overwater, or underwater. The only way you can tell is to check the soil well into the pot, not just on the top; more like all the way to the bottom of the pot. Don't water until the soil feels cool, but not wet. And when you water, water enough that water runs out from the bottom of the pot. This way you can avoid both too much and too little water.
