Going through the Support channels will be the only process for dealing with any refund requests. As described in our Knowledgebase – http://support.envato.com/index.php?/Knowledgebase/Article/View/256/55/can-i-get-a-refund-for-an-item-i-have-purchased
As we are not able to help through the forums I encourage you to continue going through the Support tickets. Thanks!
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!