Urgent: after backup my folder/files to this SSD, all data is gone from my local machine

I have a Windows 7 desktop and want to have an external drive for the backup.

I purchased this product two days ago from Amazon and today I received.

Connected as G:

Copy a folder (~400GB) directly to the G:, denied saying additional 150GB needed.

Click on the SanDiskSecureAccessV3_win.exe, takes a very long time, and then a tool opens prompting me to just drag and drop into the vault area? which I took the assumption just like all the regular connected drives like USB or SSD drive.

After a few hours, I came back and it is showing done.

However, the folder and files are no where to find out.

Even more surprising is ALL THE FILES on the original place on my Windows 7 are GONE!!!, only folders/subfolders remain there.

This is a disaster to me.

Can anyone please help to sort it out?

Can anyone please help to sort it out?

Can anyone please help to sort it out?

I must get my data back…just cannot afford the lost.

Heartful thanks here.