I listened to the iphone on the train on friday, got to the station and shut it off. But, I noticed that when I hit the top button it didn't make the closing noise. I then received a phone call and couldn't hear the person at all. Tried speaker phone and no good. I tried to play music without the headphones and still no sound. I had to turn it back on and take the headphones out while it was on before it would work again. Anyone else has this problem?