I previously said, above:
The one ray of hope seems to be that there are cross-distro efforts (for all linux distros, not just Ubuntu) for the Samsung ARM Chromebook here:
I mention this because you could potentially "Report a Bug" there. But it sounds like you have only a vague description of what's happening to you so far. You have no specific error messages to offer, as seen in various log files from within Chrubuntu. And it'll be damned hard to access those log files from where you're at now. But at least perhaps you can help get the ball rolling. The so-called "Samsung Chromebook (ARM) hackers," who monitor those Bug Reports, might then be able to suggest tricks to help you obtain these error messages.
Oops, you probably shouldn't create a bug there, because you don't have an ARM CPU in your Acer C7 Chromebook.
But everything else I said is still valid, pertaining to how Chrubuntu is currently very, very "unofficial," and support options generally don't look good at present.