Macintosh HD(disk0s2) won't mount
I did a mistake in terminal with diskutil and i unmounted my disk0 which is the OS partition and when i rebooted the system,the os didn't come up.i tried cmd+r and gone to the internet recovery and there i tried to mount the disk0s2(which my OS and my data is there) from terminal(with "diskutil mount" and "diskutil mountdisk") but i couldnt mount it.i tried"fsck -fy".I searched a lot but i got nothing. is there anyway to mount the disk0s2 ? if there isn't , is there anyway to rescue my data from the disk0s2 and then reinstall OS ?
MacBook Pro (Retina, 13-inch,Early 2015), macOS Sierra (10.12.3)