SIM is not working on S3 NEO GT-I9301I

Today, i have bought a branded s3 neo GT-I9301I for my mother. Everything is ok but sim is not working on it. I tried different SIMs of different networks but no results. Each and every time it shows a message "not registered on network".
And it is v strange that on the shop sim was working but after reaching at home i put my sim and boom that message showed up.
What should i do now? I can't give it back to the seller as it doesn't has any warranty.
Help me guys.

Porting rom for gt-i9301i?

Hi xda :D I'd like to know if someone could port this rom:
http://forum.xda-developers.com/gala...t-rom-t3061428
or other roms based on TW Lollipop style. I'm waiting for NeoStockX 5.0 but we don't have any news about that rom..

Howard to change from cwm to twrp on samsung Galaxy s3 neo GT-(I9301I)

Hello

i will change on my Samsung galaxy s3 neo GT-(I9301I)
from cwm to twrp I need your help