Have you tried moving the files back to the original location? Before you do anything, may want to copy the entire project just to have a backup in case you break it more.
I’m not really sure the exact proper way to change it’s file location, but one option may be to duplicate the file you want to move, delete the original, and then when it asks what you want to do about the deleted files references, assign them to the duplicated actor. That may cause the same issue with soft references, it is good to backup a project frequently and before you do anything risky. Good luck I hope you can recover it.