To renew purchased item support you have to login to Envato with your account then go to Downloads menu screen.
Select item from the downloads screen. And you will see a Renew support button on the right sidebar of the item page.
After click on the button and pay for 6 months renew support you have to update data on our support forum.
Login to our support forum then go to your profile page
And under Envato User Information section on edit profile page there are Refresh data and Add new item buttons. Which allow your refresh purchased item data from Envato and add new purchased item to get support.