Did I totally misunderstand what an Extended license is??

#1

I did just got my theme taken down from themeforest. The because an author from codecanyon claimed his plugin was included in the theme without an extended license.

However, I have purchased an extended license some time ago, so I sent the Envato staff my license purchase verification.

The staff still wont accept this, saying, she also want a written permission from the plugin author.

Does this mean everyone including a plugin, e.g. a slideshow, both needs to purchase an extended license, and then also have a written permission to use it in their theme?

#2

Yes. In addition to an extended license you also need written permission from the author. This is as per regulation.

#3

@Typps is on point. Per the license FAQ:

With the permission of the original author an item can be used inside a larger stock item or template sold via Envato.