Thanks for your reply. the steps you mentioned have worked like a charm. My mobile works on 2G and 3G just fine.
I went to one of the local service shops here in Bangalore(India), and have forced him to just try the steps as is using SPT.
There was lot of hesitation by the service guy(just like the Samsung service guys), but I had asked him to just do it and at the end it just worked.
Thanks a bunch. I am so happy