It just has to be paired correctly. When you first turn the switch to bluetooth mode (after you open the box) the light blinks fast and you are in pairing mode.
But, you can't just turn it off and back on to set it in pairing mode again. The light will blink slow if you do and this will be connection mode.
To place the headset in pairing mode again you need to:
1. Set the slider switch to the Bluetooth icon.
2. Slide the track switch to "Next" and hold while pressing and holding the "Volume up" button at the same time.
3. The link LED indicator blinks rapidly and you are ready to pair again.
Other than that, I would be really careful with the RAZR because a quick browse through other forums shows that these users get similar issues with bluetooth connectivity. I would stop by a local Best Buy or something and see if you can test it out before you actually purchase it.