Phone [Q] Not Able to upgrade from Gingerbread to Jelly Bean Galaxy S2 9100G

I was using Ice cream sandwich in my mobile. I tried Rooting my Galaxy S2 9100 G but it failed and was not booting anymore. I tried everything including taking it to Download mode and all, but in vain. So I went to a local mobile repair shop. They said they flashed this mobile or something and Now it is back to Gingerbread. When I try to update it to latest firmware, It is showing there is no update. Also, when I connect to Kies, it shows a message that Firmware version is not supported. I'm not able to update to Ice cream sandwich or Jelly Bean. I also thought os trying cyanogen mode, but it says minimum requirement is to have stock 4.1 version. Please help me....