Do you use Lite or Pro version?
If you use Lite version please enter your tab name into ‘Name of your tab’ field of WooCommerce Custom Tabs settings page, lite version displays only this tab!
(I suggest to deselect “Enable evaluation of multiple tab administration” checkbox, to switch on evaluation functions that is not displayed on front end in the Lite version. You can find more information about this in the documentation: https://webshoplogic.com/products/wordpress_plugins/woocommerce-custom-tabs-lite-plugin/#tab-faq )
If you use Pro version I have not got enough information to find out what is the problem.