You could try to force your headset into the pairing mode. In order to do it, with it turned on, press and hold the answer/end button for some 5 seconds, until the bluetooth indicator light is rapidly flashing. It is in pairing mode now. Then, withing the next couple of minutes, bring your phone close to your headset, and make its bluetooth application search for new devices. After a little while, your headset should appear on your phone' screen. Select it and command it to connect. If a pairing code (or PIN, or passkey) is requested, enter '0000' (four zeros). If the pairing process is successful, your headset will enter the stand-by mode. There could be an indication on your phone too, that a headset is connected.
Hope you are able to sort your problems out soon.
By the way, if your headset's user guide happens to be missing, feel free to download it from this location
Anyway, please, let me know if I can help you any further.