iphone 4s singapore

I have an iphone 4s bought in the US and I am trying to get it unlocked so that I can use it in Singapore. The person who sold me the phone replaced the sim card slot with a gevy slot. When I insert a singtel sim a message pops up "Only compatible sim cards from a supported carrier maybe used to activate iphone" I restored the phone via itunes and currently stuck with the language selection screen. When I go ahead trying to activate the same message pops up. I do not have the parent sim or att sim which I used when I was in USA. I have another iphone under contract in the US but I bought this from a 3rd party and was not able to get it unlocked via att.If the OP or anyone else guide me as to how to unlock my phone that would be very helpful.

PS- can anyone confirm that unlocking does not void my apple care plan.

 

Thanks for the reply. Why would you want me to exchange my phone when I can just use the gevey sim to get it unlocked. Actually I have the gevey tray instead of the sim tray given my apple. But the gevey sim tray that I have is just a metal casing with no sim or additional material(just the empty metal case). Is this an old model GEVEY? Anyways my iphone is stuck in a unique situation that I tried restoring it with the new sim and I cant activate it. In other words I am stuck at the language selection screen. Do you think the Gevey still would work for me?

PS-can you tell me where I can buy the GEVEY sim, I live in singapore and need to get it shipped to me

 

While I appreciate your two word answer, can you please also confirm few of my doubts from the previous post.

Thank you.

PS- Can i still use gevey even if I am at the very first stage of activating my phone(language selection screen)