The file or directory is corrupted & chkdsk not working.

Hello,
Please i 'm having issue with my external hard disk 600GB. It seems to be a common error message when you unplug external storage devices without ejecting it first from the computer. Its prompting for formatting and after which i cancel it from formatting, the drive shows

I:\ is not accessible
The file or directory is corrupted or unreadable"

After searching through forums, i came about using chkdsk /f i: ---

This command seems to work for everyone but mine is not working. I get this message from the command window: The type of the file system is NTFS. unable to determine volume version and state.

Please, i will appreciate any effort in fixing it because i cant imagine the harddisk to be formated. Thanks