Hi. My partner has an iPhone 5 which is about 6 months old. She didn't make that many phone calls until recently but that has changed. We don't know when these problems started but think they have been ever present. What happens is that during the call after a random amount of time (very few calls she makes are trouble free) she starts to either hear the other person dropping in and out or they can't hear her for periods of time. Yesterday this happened 10 times in an hour long phone call. This happens everywhere, not just in our house so isn't mast/network related. Apple have replaced the phone once and I have had a replacement sim from O2. The signal never drops below 2 bars in our house. The problem still remains. She never had a problem with her 3gs and I don't have a problem with my iPhone 4 when in the same areas she has had problems. My last dealings with Apple were for them to try telling me that I needed to restore the phone as new as the problem must be in the backup if it still persists on the new phone. I did this and the problem immediately resurfaced. Unfortunately, I cannot replicate the problem. I have borrowed the phone and used it at home, work and on the move but have never experienced it. This could be because I tend to test it after restores/restarts etc. but she has problems immediately after restarts etc. I know it happens to her every time though as I can hear it happening when we talk to each other on the phone. I really need to take the phone from her when she is in the middle of a problematic call as that would prove to me once and for all (unfortunately a lingering doubt remains) that this problem is not akin to the iPhone 4 aerial problem and she simply isn't physically compatible with the phone (I know this sounds ridicuous and I have her had try it held in different positions, speakerphone and bluetooth and the problem still occurs). I'm not sure what's going to happen if apple look at it again, can't replicate the problem and replace it only for the same problem to reoccur. We have tried hearing aid mode, wifi off, 3g off etc but still nothing works. I was surprised to find the other day that there is a data flat spot on my journey where there isn't even an o, let alone E. In this flat spot the phone will not make outbound voice calls even though mobile signal is at full strength...is this normal? Thanks for your help in advance.