I just arrived in Hong Kong and I brought my Verizon iPhone 4S with me. I had Verizon unlock it for global use before I left. Anyways, I just bought a SIM card so now I have service, but I'm a little confused as to how to use iMessage on this. When I open up my messages app, many of the threads have lost their contact titles so I don't know who I'm texting (some of them still have their contacts associated). Also, looking in settings, my receiving number changed to my Hong Kong number. Does this mean people can't iMessage my US number anymore? How do I use iMessage to reach them? And how can I use my Mac for iMessage as well? I've never brought a phone with me overseas so all this help will be appreciated.