I too have had this problem with my 2012 Rondo when plugging in the iPhone 4 via usb cable. I now use a dedicated iPhone charger cable I have for charging, and for playing the music, I simply use the bluetooth wireless, or plug in the headphone jack cable into the phone, and the other end into the aux input on the stereo, but usually I just use the bluetooth as it works fine. For some reason, the usb doesn't want to work, and will not charge or play music like you said. You're not alone lol!