Sorry to hear about your problem. It is atypical for Neptune to be unresponsive. When I had a similar problem, they suggested that I buy a power supply for the controller. I was switching controllers from one tank to the other and in doing so, I experienced a problem similar to yours. Once I did that I was able to see the controller and from there they were able to help me. Not smart enough then to reconfigure the controller which I believe that is what they did and everything worked from there. Quantum Reefs may have them but I got mine at Radio Shack. Just make sure you get the specs and bring your controller to ensure you get the proper connector.
What I think happened: You lost power to controller and the controller rebooted and consequently relabeled your EB8. Once that happens, the controller stopped communicating with the EB8. To fix this you need to access the controller with a dedicated power supply and remove the eb8 modules and have them rediscovered. Follow the instructions when doing this. Hopefully everything works. Once you get it to work, save the configuration for future use. Hope this helps.