Are you a Verizon customer?
If so, and if you meet the requirements, call Customer Service for the code.
* Must be a Verizon Wireless customer.
* The iPhone 4S being unlocked must be active on a Verizon Wireless line of service.
* The line of service must be active at least 60 days.
* The line of service must be in good standing for the past 60 days.
* Only one SIM Unlock per line every 10 months.
Read this thread for details. https://community.verizonwireless.com/thread/696707
If you are not a Verizon customer or if you do not meet the requirements, you will need to contact a third party unlocking service and purchase a code.
Hallo, i'm an Italian guy and my brother has gifted to me an used iPhone 4s bought on ebay: I tryed to use it with my sim, as soon as reach a comunication signal, the phone start an authentication process and end to inform me that the phone is enable to roaming on USA and the inserted sim is not supported. Calling the Italy Apple customer service the operator has informed me about the locked phone on Verizon service (Verizon 14.0). I'm not a Verizon customer and the only information that I can give is the IMEI...Also, I'd tried to contact a third party unlocking service to purchase a code, but without result. Is possible to unlock the phone and leave me the possibility to use it in my country on my gsm/3g sym? Thanks.
Verizon will not provide the unlock code for you unless you are a Verizon customer and meet the requirements.
If you are unable to obtain an unlock code from a third party company, then your best option would likely be to sell it and get a phone that is compatible with your phone service provider.