We provide license key of Visual Composer in download package. We bought extended license of this plugin but current have note solution for activate with this plugin, license key only can activate one time.
Here is the license details of WPbakery:
It is not possible for theme buyer to activate the license (and hence to auto-update the Visual Composer) as they have not purchased the license directly from us, but has received it in-directly from the theme. In this case, you must update the version in the theme and must release a theme update which the buyers can download and hence in-turn will receive the latest version of Visual Composer.
Wea��re sorry about this inconvenience but we will update our themes to run follow Visual Composer updates.