I have checked your website and your code and you haven’t the last update of the plugin. If you download it again and update it, the problem with the contact button will be resolved.
About the translations, you can set up the plugin from the plugin editor. Go to the page ‘Plugins > Editor’, select the plugin ‘Verde’ from the dropdown component at the top right, and finally look for the file ‘verde_plugin/themes/language.php’. In this file, you can edit the texts to translate.