Thank you for your reply.
it’s not quite clear to me what I should do.
shall I physically take out the hard drive from the My Cloud casing and connect it to a PC with a Linux OS?
I am a windows user and I have no clue about Linux. can you please explain how should I browse into my hard drive and find the folders? does Linux have a special tool to show the deleted files? I have an extra PC which I can install Linux on it but I don’t know how to recover the file in Linux.
I already asked WD for support but I still got no feedback.
Do you have access to a external USB enclosure and know how to use it to connect a spare disk to a computer?
You do NOT need to install linux OS on your computer. Many linux vendors provide a bootable CD image that you can burn on a CD-RW and boot your computer with it without affecting your Windows OS on your C:\ drive.
You either need linux OS or install drivers that can support read/write of ext4 linux partitions to be able to browse your disks that are currently installed inside Ex4.
If you are not able to complete this setup prerequisite, I would suggest looking into the advise above by skiwi since it appears that retreiving data back is very important to you.