I have an Iphone 4s that has an Audio problem. After dialing someone I cannot hear the phone ringing them. I am convinced it is a hardware problem as I have restored the Iphone. The person that I have called also cannot hear me talking. What are the possible hardware issues that could be the problem. Shouldn't this just point to one thing? I have replaced the ringer, charging port, but had no luck. Thanks for any advice.