Hello, one of my sites went down need help fast.

Hello This client’s site is down. I’m not sure what version of Enfold is current. I had bought the theme twice, and one of them no longer exists. I renewed support for one of them but do not know if I renewed the wrong one. This is what we get when you go to the site,
Fatal error: Uncaught Error: Function name must be a string in /home/tilliest/public_html/wp-content/themes/enfold/framework/php/class-style-generator.php:123 Stack trace: #0 /home/tilliest/public_html/wp-includes/class-wp-hook.php(286): avia_style_generator->create_styles(”) #1 /home/tilliest/public_html/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array) #2 /home/tilliest/public_html/wp-includes/plugin.php(465): WP_Hook->do_action(Array) #3 /home/tilliest/public_html/wp-includes/general-template.php(2745): do_action(‘wp_head’) #4 /home/tilliest/public_html/wp-content/themes/enfold/header.php(47): wp_head() #5 /home/tilliest/public_html/wp-includes/template.php(722): require_once(‘/home/tilliest/…’) #6 /home/tilliest/public_html/wp-includes/template.php(671): load_template(‘/home/tilliest/…’, true) #7 /home/tilliest/public_html/wp-includes/general-template.php(41): locate_template(Array, true) #8 /home/tilliest/public_html/wp-content/themes/enfold/template-builder.php(12): get_header() #9 /home/t in /home/tilliest/public_html/wp-content/themes/enfold/framework/php/class-style-generator.php on line 123
The site is experiencing technical difficulties.