Error on plugin activation

Hi plugin isnt working, Following error appeared.

An error of type E_ERROR was caused in line 3 of the file /home/miniglrh/public_html/wp-content/plugins/ipay-for-woocommerce/class-wc-gateway-ipay.php. Error message: Uncaught Error: Class 'WC_Payment_Gateway' not found in /home/miniglrh/public_html/wp-content/plugins/ipay-for-woocommerce/class-wc-gateway-ipay.php:3 Stack trace: #0 /home/miniglrh/public_html/wp-content/plugins/ipay-for-woocommerce/ipay-global-payment-gateway-woocommerce.php(29): include() #1 /home/miniglrh/public_html/wp-includes/class-wp-hook.php(303): init_ipay_global_gateway_woocommerce('') #2 /home/miniglrh/public_html/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters(NULL, Array) #3 /home/miniglrh/public_html/wp-includes/plugin.php(470): WP_Hook->do_action(Array) #4 /home/miniglrh/public_html/wp-settings.php(441): do_action('plugins_loaded') #5 /home/miniglrh/public_html/wp-config.php(97): require_once('/home/miniglrh/...') #6 /home/miniglrh/public_html/wp-load.php(50): require_once('/home/miniglrh/...') #7 /home/miniglrh/public_html/wp-login.php(12): require('/home/miniglrh/...') #8 {main} thrown