I contact the customer service on TM WooCommerce Extra Product Options and they said :
(The problem is your theme. In the file /themes/xstore/woocommerce/single-product/add-to-cart/simple.php it uses the action woocommerce_before_add_to_cart_button two times which is wrong. I can fix the template but you should contact the developer to fix this so that you won’t have the same issue with future releases of the theme)
Can you Plz check that ?
Site URL: hidden Theme version: xstore WooCommerce version: last one