In Linux...when you move a file, you're fucked.
Their fault for not having backups.
That's not true. Depending on which filesystem they are using, it can be just the same as recovering lost files from a FAT16/32 filesystem (ext2 uses similar mechanism to "delete" files), or a bit more complex requiring parsing filesystem journals and reconstructing from meta data.
In all cases, the most critical step is to stop writing to the disk as soon as the mistake is discovered. Yanking the power is better than a "proper" shutdown in this situation