WD Red Nas 3 To - Reduced disk space

The available space of my WD Red Nas hard drive (WD30EFRX) went from 3To to 802 Go when I wanted to add this hard drive in a Lacie external box. I have the impression that the Lacie box has modified the firmware of the hard drive. I formatted several times without success.
Thank you in advance for your help and I hope that there is a solution to reset the hard disk size.