Hi @boazpeled, thanks for reaching out.
Indeed, our plugin does support Negotiated Rates.
The issue might be related to a theme you are currently using in your store. To check if there is no conflict, please temporarily install and enable Storefront the official WooCommerce theme, and see if the problem persists.
Alternatively, the problem may be related to some other plugin used in the shop.
Please disable plugins which are not ours or the WooCommerce itself.?Then please enable plugins one by one,?deleting cache, and check if the problem still occurs.
In order not to influence potential customers with your actions,?you can use the so-called staging. This is a secure 1:1 copy of the site, intended for testing and invisible to customers. Many web hosts provide this feature. If your web host does not offer this, then you can use the free WP Staging plugin.
After checking the above, please?let me know about the outcome.
Kind regards,
Piotrek