umount -f works but target is busy (Also GParted can not check it successfully)

Question

Try to umount -f /dev/sda7 as said here to do sudo e2fsck -C0 -p -f -v /dev/sda7 based of comment of my previous question i get this error:

root@ubuntu:~# umount -f  /dev/sda7
umount: /dev/sda7: not mounted.
root@ubuntu:~# sudo e2fsck -C0 -p -f -v /dev/sda7
/dev/sda7 is in use.
e2fsck: Cannot continue, aborting.


root@ubuntu:~# dmsetup ls
No devices found

also cannot to checked successfully by GParted as could be seen here:

Also based of this post i get no output!!:

If possible, let's locate/identify the busy the process, kill the process and then unmount the samba share to minimize damage.

lsof | grep '<mountpoint of /dev/sda1>' (or whatever the mounted device is)

pkill target_process (kills busy proc. by name | kill PID | killall target_process)

umount /dev/sda1 (or whatever the mounted device is)

lsof: WARNING: can't stat() fuse.gvfsd-fuse file system /run/user/999/gvfs
      Output information may be incomplete.
root@ubuntu:~# lsof | grep /dev/sda7
lsof: WARNING: can't stat() fuse.gvfsd-fuse file system /run/user/999/gvfs
      Output information may be incomplete.

Also can not format /dev/sda7 by GParted :

Thanks.