Change bundle id for purchased license




we purchased one license and requested a key for our bundle id for a Unity/iOS project. Everything worked fine but now we found out our bundle id is already occupied. We can’t add the app id on the Apple developer portal.
When I request a new key for a different bundle id on the kudan website I get one but Unity says it’s invalid. Can I somehow change the bundle id/key or is it only possible once? If so why would Kudan give me a second key on the website?