Was it recently shipped? It might be having a reaction to to a major change of climate. What about the light and/or fresh air? I would take it out of it's pot to examine the roots. It might have been watered too much before you got it. I would keep it in a bright spot with no direct sun for a while, with plenty of fresh air, not too hot or too cold, and watch the watering carefully. Or you might just bring it back and ask for a replacement or a refund. I hope it revives for you. Jerry