I am on Joomla version 3.8.2 with Php 7. I tried to upgrade to CiviCRM 4.7.28 but it failed because it was partially installed and missing important files. Now, I can't get into the Joomla administration back end to reinstall it or delete it because when I log on to the admin, I'm getting a black white screen that when I turn-on debugging, shows the error message. Subsequently, I can't do anything with the site.
My question is how do I delete civiCRM or reinstall it without doing it through Joomla?