I have a Motorola Elite Flip bluetooth that I have paired with my new S4 and I'm having some problems. I set up auto-answer and that works, but the mute/unmute button on the headset is not fully functional. I CAN mute; however, when I press the button again to unmute, the voice connection disappears--it's neither on the headset or the phone. The only way I can figure out how to make the voice connection come back is to turn the headset off and then back on. This feature of the bluetooth worked perfectly with my Bionic, it works with my daughter's Galaxy S3, and it also works with another daughter's LG phone. I've tried restoring the bluetooth factory setting and then re-pairing it with the S4, but that didn't work. I use my bluetooth for about 4-5 hours a day, and being able to mute AND umute with the headset is critical to me. I would sure hate to return my new phone over what seems like such a small problem, but I'm thinking I might have to do that. Can anyone offer any other suggestions?