Rescue files

Hi!

I am trying to rescue files from my NAS. My flashdrive is corrupted. Has not got help for this yet. I booted on Centos and run:

# mkdir /mnt/lvm

#  vgs

# lvs
# lvdisplay
# vgchange -ay
# mount -o ro /dev/mapper/c-c /mnt/lvm

When I check df:

# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 1.9G 0 1.9G 0% /dev
tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs 1.9G 8.8M 1.9G 1% /run
tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
/dev/mapper/centos-root 26G 1.6G 25G 6% /
/dev/sda1 1014M 192M 823M 19% /boot
tmpfs 379M 0 379M 0% /run/user/0
/dev/mapper/c-c 9.1T 8.8T 198G 98% /mnt/lvm

I see /dev/mapper/c-c using 9.1T

From /mnt:

du * -skh
8.8T lvm

lvm usig 8.8T

But from /mnt/lvm:

# du * -skh
8.0K aquota.group
8.0K aquota.user
12K home
16K lost+found
16K media

Where is the files?

Help realy apprechiated!