First, please find some other way to share what you see other than a word doc.
*all* of the methods for disabling the maintenance mode shared on the link you've referenced do work ... I just tested again with a Moodle 3.3.2+ and all continue to work.
Perhaps the easiest for you is the editing of config.php and adding the following line:
$CFG->maintenance_enabled=0;
Insert the line above, before the line that shows:
require_once(__DIR__ . '/lib/setup.php');
But, am not at all sure that will fix IF it failed to upgrade. Not sure I've seen 'Non zero exit status returned by script' before when upgrading as per Moodle.org recommendations - using Web or CLI.
It appears your provider has provided a script to upgrade moodle ... unless someone here host with same provider and has Plex (or whatever the cPanel is) and tried the same thing, most of us would have no knowledge of just how that script attempts to upgrade.
Evidence of that ... the version number reported. In version.php file of your site's /moodle/ directory, which should be moodle code, the version.php file has this: $version = 2017051502.02
Looks nothing like 3.3.1-91.
Appears your situation is between a rock and a hard place, but for reasons given above, I'd say you'll have to get assistance from the provider.
Hope you began the process with a full site backup first.
'spirit of sharing', Ken
