I’ve read the whole thread, and I agree that having 9 GB of files missing, and permissions reset on others, is a problem - what I don’t get is where/how this is a matter or “incompetence” on the part of DH.
I kept expecting to read how DH had done something to your files, or something to that effect, but all I see in your posts is that neither you nor DH know what happened.
It’s a bad situation to be sure, but I don’t think it’s fair to start assigning blame or maligning others’ competence until/unless you can explain how they are involved/responsible for what happened.
Have you reviewed your access logs to make sure that you had no unidentified access to your account? How do you know that your account/password was not compromised? Do you use ftp or sftp?
The missing files are a bummer, and DH may, or may not, have had something to do with how that happened, but you have not explained at all how you believe that their “incompetence” is related to the issue.