Download tickets won't try again until it's no longer hung or it's been 6 hours. If it's disabled though, it won't try to run.
My suggestion is to enable error reporting in your config file, disable your automatic cron, and then run the cron manually. If there are errors, it would spit them out and hopefully give you more information about the issue.
1. To enable error reporting, edit /config/blesta.php and change
Configure::errorReporting(0);
to
Configure::errorReporting(-1);
2. Disable your cron
3. Run the cron manually under Settings > System > Automation.