You'll have to buy it again. I had the same problem and they told me nothing could be done. Sorry!
I highly doubt that. Support is pretty could about helping with CD key issues.
i bought sins of a solar empire, pluys both expansions . i haven;t played them for several months . But they are no longer activated and they ask for a cd key again , but ive already activated them 2 years ago.
Can you still see them in your "My Games" in Impulse? If so, you can get the CD key from there.