What makes you think the defacement you describe is the result of some insecurity on the part of DH? You have not provided any information about what your site was running. If you had nothing on your site but HTML code, it would still be unreasonable to automatically assume tha the defacement was the fault of DH, until you can prove that your account passwords were not compromised via social engineering, your use of insecure telnet access over wi-fi, etc.
Have you looked at your logs? Have you inspected your directories via SSH and looked for file modification dates. added files, foreign scripts, etc.? What have you done to determine the cause of the defacement?
It is unfortunate that you are experiencing this problem, and there are those of us on this forum that are willling to help, but we cannot help you if you will not help yourself. Being upset at DH about it, until you know what happened and how it happened, is pointless.