Friends, everybody! I buy iphoe4 recently upgraded the system it seems to be locked in the American telephone and telegraph company (AT

Friends, everybody! I buy iphoe4 recently upgraded the system it seems to be locked in the American telephone and telegraph company (AT&T)... Because I can't find it in his hand that activation of the SIM card so far shows no service to system relegated to 6.1.4 (10 b329) baseband version: 04.12.09 although he is old now but I still like I Want unlock my an hope engineers do me A favor I have no AT&T number thank you equipment list of IMEI number: 012339000540730 model number: MC608LL/A serial number: 85025 jgua4s main name: yao E-mail: 137402276 @qq.com organization name: LENOVO