I'm afraid that is a goner. If there aren't any roots at all, there just isn't a way to save it. And it sounds like it was already near death when you purchased it--so don't blame yourself. Sometimes they are just beyond saving. Sorry, I know that isn't the news you wanted to hear. :hugs:
Next time, get a good healthy one before the store manages to kill it and you and the plant will be very happy together.
