Well, it could be the controller but: Any time I put a headset into my controller, people can hear me but I can't hear them through the ear piece. I tried new batteries, and no luck. Any ideas on how to fix it?
Check your parental controls....This happened to me and the parental controls are defaulted so that only your friends can hear/talk to you.
Well first off is it a wireless headset. If it is the wired headset that comes with the xbox...I hope you bought the extended warranty because those things break uber fast.