Hi Folks, I bought an unlocked 32g IPhone 4S from the Apple store at the beginning of November. The phone works great except for the actual phone feature. When I make/receive a call the call quality is fine and the conversation happens but I am unable to end the call, switch to the keypad, speakerphone, etc. Nothing on the screen responds, it will blink to recognize that I am pressing it but nothing happens. This is a particularly big problem because I live in an apartment building and am unable to buzz people in when they call from the lobby, also, I work from home and am often making several calls a day and am unable to end the call when it goes to voicemail and I do not want to leave a message. The only way to end it is to restart the phone completely in the middle of the call (lock button+home button). If I am finished a conversation and the person on the other end of the line disconnects, my phone will end the call and revert back to my homescreen but I am unable to click/access anything on it until I lock the screen and unlock it or restart it. I have AppleCare and the phone is still under warranty. I have called Apple and they instructed me to wipe the phone and do a factory restore, that didn't work. Yesterday, I went in to the Apple Store and they replaced my phone. This morning I made a call and the problem is still there. Unfortunately, it doesn't do it every time and it didn't do it in the apple store when I was there (with either phone) Has anyone experienced this??? Any advice at all??? I am at a complete loss. I want so badly to love this phone but at the moment I am trying to keep my anger in check that I spent $800 on a phone that can't be used as a phone. PS. I am in Canada and my carrier is Bell, but I don't think that would effect the function of the hardware.