How can I get a replacement Alienware TactX Headset? (still under warranty)

I have looked everywhere I could think of, tried calling tech and customer support, but I cannot find where to get a replacement. About 2 days ago, the audio in my headset stopped working. Every once in a while, if I twist the cord, I can get audio out of it, and It's not my computer's problem, it happens with other things too. It seems to be a problem with the wires near the jack, and the microphone works fine. Can anyone tell me where to get it replaced? I have tried to go through everywhere I could think of, but it doesn't have a service tag so  can't get to tech support and customer service and order support have been no help either. I bought it about 1 1/2-2 months ago with my Alienware m14x.