iPhone headset mic button not working
I discovered that the contact was not flush with the top of the iPhone but was a little bit above. When I looked inside the headphone jack with a flashlight it looked somewhat strange at the bottom. I straightened out a paperclip and managed to fish up a small lump of pocket lint that had probably been forming in there for half a year or so. Just wanted to deliver this as a tip for anyone who runs into the same problem, before you send your headphones back to Apple as broken as so many people seem to have done.