iPhone 3GS upgrade to new iOS 6 is locked the iPhone

[raghunk]

Hi,
Was trying to upgrade iphone 3GS to IOS 6, the phone is unlocked but right after the upgrade apple is failing to activate my phone asking me to insert the SIM card even though SIM is there in already and asking me to contact apple support and I need serial number now to contact even apple support which I did not save it.
I guess it is locked now, any advice please how to proceed
from here, any help is greatly appreciated.

Thanks.

 

[Cebuano1976]

eBay vendors unlocks iPhones for cheap. look up unlock_fusion.