I once unlocked my iphone and used for a while with US T-Mobile SIM card. I have a friend who wants to buy my phone, so I was trying to refresh the iphone by doing restore process. Now I can't do anything with my iphone. It won't let me do restore to any firmware. Everytime I tried to restore to any firmware, I only get error messeges. Once it went thru few process and gave me activation screen without WiFi and "iphone can not make or receive call" error messege. Please someone help me. Thank you very much in advance.