If you have root access - can ftp the server or ssh and use vi or nano to edit.

'/var/cpanel/userdata/vybz/vybz.live.php-fpm.yaml'

is actually - /var/cpanel/userdata/replace_with_acct_name/your_domain.tld.php-fpm.yaml 

and add the following line - 

php_admin_value_disable_functions: { name: 'php_admin_value[disable_functions]', value: none }

at the bottom of the file.

Hope this helps