Hi, basically my iPhone has a problem, it cant receive calls, most of the time it goes straight to voicemail. So i called o2 and they said everything is ok on their side. And i tried my o2 sim card in a friends iPhone and it worked fine. So there is definitely something wrong with the iPhone. Also whenever someone tries to call and it doesn't get through my balance pops up. Anyway i restored it as a new phone and it still has the problem. I went to a Apple retail store and they said they can't do anything about it as its probably got to do with the network, even though i told them my sim works fine in a different iPhone. So they tried to call me and out of the million times people have tried to call, this one did actually go through. But now i home again and tried to call and it goes straight to voicemail. At home i have full signal, and it even doesn't work outside. So what excuse can i use to get it replaced cause they are not accepting this one, so i know that means i will be lying, but if they don't know how to do their jobs and realise theres a fault with the phone as when i put my sim in someone else's iPhone it works fine.