I’ve read well and understand your issues. Therefore I asked you to try it on a default theme.
The ‘remove’ link should not be visible, the coupon should be automatically, but it seems you have an issue on your setup. Therefore please try with a default theme like Storefront or Twentysomething.
You forgot to tell me which version of flatsome you are using. Even better, please send me the WooCommerce System Status Report.