Add To Cart Button Missing
If the Add To Cart button is missing on your site, go to the WooCommerce > Single Product section of the customizer and click the eye icon for Quantity & Add To Cart. After doing that, reload your customizer and you can see a problem, only the Widgets section is loaded, to fix this, download this plugin and install it on your site: owp-fix-customizer-issue.zip
After the plugin activation, that will reset the single product element positioning setting and will fix the customizer issue, when it is done, you can go to your plugin page and delete the Ocean Fix Customizer Issue plugin.