@druuna Many many thanks to you. The links you sent helped me a lot.
Yes, I am able to recover my files. I haven't checked yet whether all are recovered or not but yes a few I have checked are recovered. As there are many many files which are recovered via that tool/command I need to grep some text pattern in those files and see which are mine. The files are recovered with different names (may be generated by system). The command is photorec
This will open a text based window. I followed the instructions and yes it's superb.