It worked! I've installed the stock rom and my IMEI is showing and the sim card is ok. Thank you all. But i have one more question:
I don't intend to continue with stock rom and stock kernel. What should i do to prevent this error occur by installing any custom rom or custom kernel? I've heard that i have to backup the efs, but the efs folder is always blank on galaxy y.
you can backup your efs partition with galaxy toolbox but that wont help you with the problem you had
I keep saying its to do with the ril - you cant use an old kernel with a new firmware and vise versa
to solve this if you use an old kernel with a new firmware replace the ril lib of the new firmware with one from an old firmware
Iv even posted them