My right earbud has stopped working. For a while, the sound would come back when I turned my head, then it would stop again. And last week, without any music playing, I could hear voice prompts for about five minutes. But now it's completely dead on the right side. No sound at all. I think my Sena headphones have just passed their warranty expiration date. Have you ever had this problem? Sena's planned obsolescence is a scam. Please help me.