Uninstalling JoomBri extensions is similar to uninstalling any Joomla extensions. Please make sure you back up your website before doing any uninstallation operation.
Steps to uninstall
Login to Joomla back-end.
Navigate to System → Extensions under Manager.
Search for "JoomBri Freelancer"
Check the first item and click on "Uninstall" button.
Do not install plugins and modules first. Component needs to be uninstalled first and this will automatically uninstall the plugins and modules.