Looks like it was old school shared web hosting with things like WHMCS, Cpanel, Softaculous, Wordpress one-click installers, in-house written web admin, etc. Where each user was running in the same instance of Linux. Not, for example, a VM per user. That kind of setup has a really wide attack surface. Not surprising it was hacked. That kind of setup with deliberately narrow support was bound to get hit.
Edit: Apparently their "sister company" sells virtual private servers, and appears to still be alive. http://nosupportvpshosting.com/index.php