In both 4G on and 4G off modes, my iPhone 5S will only connect to GPRS, EDGE (and in 4G mode) 4G. I have visited locations that I know for certain my old 4S picks up 3G, and have used other people's iPhones at the same time that are connecting to 3G. This phone is brand new and I chose to have a clean start - no restoring from backup. I have turned the phone on and off, reset network settings - the problem persists. Is this a network or hardware issue? What can I do? Thanks.