If anyone has problems with code 0000, just make sure that the headset is in pairing mode, which is power on, green light on top, then bluetooth on, hold for 5 to 10 seconds until alternating blue and orange light, then try the pairing. Otherwise, the error message may come "That PIN does not work, please try connecting again". but the PIN is fine! After 5 tries, the same PIN works! 0000 works, after several messages saying it was wrong!
So get into pairing mode, alternating amber and blue light on the bluetooth, then try the PIN a few times.