You maybe need potting soil for nutrients and maybe more water more sunlight would maybe help if it can take if it can take up some to absorb it.

First, does the pot the plant is in have a drain hole in it? If not immediately move the plant to a pot with drainage. You can check for overwatering by slipping the pot off the rootball. If it looks like soil with roots through out the soil, you've not overwatered. If the soil smells rotten and roots are only near the surface of the soil, then you've overwatered.

The changes you are seeing could be due to change from the store to your house. Differences in amount of light, temperature, humidity are all factors that can cause leaf drop. Hopefully it will adjust and resume growth.

Lots of water still doesn't mean every day usually unless its a wetlands plant. Keep it moist but not WET. Also, it doesn't like to have direct sun because that can make the leaves curl and burn so consider that if it gets direct sun often throughout the day.

Here's a link with some good information. It does mention misting it often, so it sounds like a light mist is ok for it.