Plugin is crashing web-site when WooCommerce not activated

Hi

This plugin’s crushing web-site when WooCommerce plugin is not activated

Woocommerce Plugin Not Activated
Fatal error: Uncaught Error: Call to undefined function WC() in /var/www/vhosts/……./httpdocs/wp-content/plugins/omise/omise-woocommerce.php:116 Stack trace: #0 /var/www/vhosts……………/httpdocs/wp-includes/class-wp-hook.php(286): Omise->register_user_agent(”) #1 /var/www/vhosts/………./httpdocs/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array)