My new 5s is having some problems, I can hear people on the phone, but they can't hear me very well. The problem is intermittent. I took it into an Apple approved repair centre yesterday and they wanted me to replicate the problem and of course it worked fine for them when they called my phone from 20m away - so they wouldn't exchange it. I guess I have to go through Apple instead, their nearest shop is 100kms away and I don't have a spare phone so can't send mine away, which I'm guessing is what Apple is going to suggest... has anyone else experienced this issue? I did notice that turning bluetooth off improved the sound dramatically, so this is probably the culprit, but obviously it's not practical to be turning off bluetooth every time you want to make a call.