My iphone 4 has an issue with the caller Id. It has not worked since purchasing my iphone in December. There is no screen that pops up when a second call is coming in to give me any options to take the call. The only thing I get is a faint beeping to know that a call is coming in! It also does not show who is calling or show a missed call. The only way I can answer the call is to hang up on the first person. I have reset the phone several times and also when I go to settings under phone there is no "call waiting" to turn off or on at all! This is very frustrating!