Dear Sony, I bought the product MDR-XB50BS last year on Amazon Mexico. Unfortunately last week the on/off button fell off at the gym . In other works, now I have a headphone that I cannot turn on/off because I dont have the button. I'm very carrefully with it, but i guess with some movement when quit from my ear, drop the button. I love it, but the product is not that cheap to break like this, I can´t use without that button. I live in Mexico city. Can you help me? Awaiting return. Thank you.