Hello If you click on the item’s support tab you can see the support options an author may provide – http://codecanyon.net/item/visual-composer-page-builder-for-wordpress/242431/support
You are welcome to use their support forum for any install questions you may have. Thanks!
In your Downloads area there is an option when you download the file to download your purchase code. That is what they are probably asking for. However, I don’t see you having purchased the Revolution Slider, so you would need to log in using the account you purchased the file under. Thanks!
I’m pretty sure Tim (for instance) has voiced his concerns on the matter numerous times over the years, even saying he might have to leave the jungle if things didn’t change. To my knowledge there was no official and public response from Envato.
We’ve responded several times that expanded licensing options was something we’re currently looking at