Iphone 4 and Clarion VX400 Bluetooth Issues

Up until about 2 weeks ago my iPhone and my clarion unit were working perfect. I plugged in my iPhone on the usb/ipod connector (once) and ever since then I am having issues and cannot hear the other caller. I have an ipod nano connected to it so its not like I use it for music. Now the callers can hear me but I cannot hear them. I hit the reset button and it worked for a bit but now its back to not working. I cannot find any help anywhere and I am getting frustrated! When some one calls the vx400 is selected as the speaker, so i don't think thats the issues and my phonebook and bluetooth connection seem fine. I have erased the one podcast I had on the phone so there is no audio on there. I am hoping someone can help me!