I have a 3GS without a SIM that was originally activated by Orange in France model number MC131NF. Got it from a friend who was able to convince his company to a 32 gig. I took it to the US without the SIM thinking that I could get it to work here. So far I jailbroke it and unlocked it and put my SIM in there but it can never find the network. Without unlocking it it says that the SIM is not the original one it was activated with. Do I simply take it to ATT and tell them that I purchased a used phone and would like to go from my 3G to the 3GS? Is there a risk that no matter what I do it will not work here in the US?