Spark Core gone from Device listing, can't add it back

Hi I have the same problem. My spark core appears as “other” device. I deleted the device, added it again using the Device ID with the same result.
The problem is that when I compile my code a previously correctly compiled code, now has errors in libraries.
Another issue I have is that I can’t claim it using the iphone app. The app doesn’t find anything when trying to claim the core.

Any help will be appreciated.

Costas