There are several "different" OpenVPN products available. Some of them use completely free open source libraries and other do use some commercial libraries. CenturyLink Cloud uses software under this license:
What is not free for commercial use is the OpenVPN Access Server. That software contains a GUI for managing connections, creating VPN download bundles, etc. CenturyLink Cloud does not use this software, allowing everyone to be covered under the community supported edition. A comparison of the editions can be found here.