The software is bundled by Gemini. MixVibes doesn't know which key was delivered with which controller.
However, you can send an e-mail to
support@mixvibes.com. Please provide the readable part of the key (e.g. photo).
Maybe this will help.
If they can fix the key for you, be sure to download the latest Cross LE version, which for the Gemini is version 2.6.