Can't mount an unlocked encrypted partition from my WD External HD

I had been using an WD 500 GB External Hard Drive for backing up my files for a while.

I used to back up files using Time Machine, but I could also copy and paste files directly to the HD.

Every time I plugged the device, the computer would ask for a password because I chose the encrypted mode.

A few weeks ago I tried to use the HD again but it wouldn't appear on devices (it never asked for the password again) , so I went to disc utility and found the information bellow.

Apparently, the disc (BackUP MAC Marina) was mounted and there were files stored on the disk, but I couldn't find a way to access them.

I tried to repair it, but it wasn't possible through disk utility.

A friend of mine took a look at the HD using a PC, but he couldn't find any files and wasn't able to solve the problem.

I don't know exactly what happened, but I think he could create a new partition on a Windows NTFS (Marina).

So, when I plug the device on my mac this is how it appears on Disc Utility:

But now, the "BackUp MAC Marina" Disc is appearing as not mounted and all the info is blank::

I've tried some moves on Terminal after reading about the subject on the internet, but nothing would work.

All the files I had on "BackUp MAC Marina" are unique, I don't have a copy anywhere else 😟

Do you think there's anything to be done to recover these data?

Has anyone experienced anything similar?

If anyone have any ideas of what I could do to try to access and recover my files (basically photos) , please let me know.

Bellow I'm attaching two screenshots I got from the terminal, just in case.

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Thank you veeery much!