Your plugin requires the Zingiri logo to be displayed on the user site, unless user have written permission from you.
"Select how and where you want to display the Zingiri logo. You can display it at the bottom of your site or a the bottom of every shop page.
Only select other if you received a written confirmation from us that it is ok to do so."
I think your requirement goes against the WordPress licensing. Any Plugins/ Themes is a derivative of WordPress. User can modify the source code and remove your requirement.
Correct me if I'm wrong.