Are you sure it's the headset that's acting up? Maybe there's a problem with the phone or the phone jack. Try the headset on someone else's phone and see if it works. If it doesn't, then clearly the headset's not working right, and you should see if you can return or exchange it. If the headset works on someone else's phone, then maybe there's some debris in your headphone jack. Take a damp toothpick and root around in the jack to see if you can pull out any lint or other debris. You could also try using a can of compressed air to blow out any debris.