Billing, licensing terms, and process is handled exclusively by Envato (the company who owns ThemeForest), and we have no control over these aspects.
The support package does not limit theme updates or plugins, it is only needed to submit a ticket on our support forum.
There are two types of theme licenses you can purchase from Envato: Regular license and Extended license:
Allows you to use the theme for one domain only. A domain is considered only the top-level domain, and you can use the regular license on multiple subdomains of that domain. For example, if you use the theme for www.mysite.com:
www.mysite.com – Valid
staging.mysite.com – Valid
mysite.com/staging – Valid
whatever.mysite.com/directory – Valid
localhost – Valid
abc.com – New license is required
staging.abc.com – New license is required
184.108.40.206 – New license is required
Allows you to activate the theme on any domain and local/staging environment.
You can read more about Envato licensing here.