My Book has been blocked!

Good day to you!
Please be informed that recently I have purchased an External Hard Drive with the following specifications;

Model Name: My Book
Capacity: 4 TB (1.5 TB used)

I have confronted with a serious problem with this device; 1st of all, I moved my video files from the Camera’s RAM into the hard drive. It’s done successfully! But when I wanted to get a backup of these files to another device, it showed an error message and then it’s blocked!! I can’t access to my files anymore and it made me worry!! Because I should deliver these files to my client.
Some technicians have also checked this problem, but unfortunately did not succeed.
May I kindly request you to help me in this respect and tell me what should I do in order to solve this problem?!
Thank you in advance for your kind attention!
Regards,

Hello,

I recommend you contact WD support for assistance with this issue.