My java moss did the same thing. After I received it, It turned brown. But after a week, it started to grow. The problem is that it seems to grow in every direction. So now I'm now planning on tearing it out and replacing it with mini-moss (I think it's also call Taiwan moss). So, I would give it another week.
But Hey, if it doesn't turn on you, send me a message. I could give ya another quarter cup to try again.