Actually we purchase the extended license of Visual Composer plugin and include it on our theme package as required plugin, so you don’t need license key for VC plugin. We’ve been adjust the VC plugin on our theme so it can compatible with our theme. We will suggest you to keep using VC plugin that come with our theme package for compatible reason.
Anyway, can you help me to provide login credentials into your wp admin panel so i can check it directly what actually happen in there. You can send it here and check the Set as private reply option below.