Spamhaus has been under attack from e360 Insight for a while now. While a UK based company, they were taken to court in the U.S. They failed to appear, and as such a default judgement was given to e360. The terms of which included a hefty fine of $11.7M. When Spamhaus refused to comply, e360 then pushed the courts to require their domain name be shut down. Everyone pretty much took a “hands-off” approach, and neither ICANN nor Tucows was willing to suspend Spamhaus's domain. Seeing no other option, Spamhaus has decided to take e360 back to court with an appeal.

But, e360 Insight's aggressive legal moves have prompted Spamhaus to switch strategy. Spamhaus has now filed an appeal against the original default judgment against it. US law firm Jenner and Block is representing Spamhaus in the case.
This will be the first time they have defended themselves. On their site they list their intention to contest the ruling. Would it have been better for them to defend themselves from day one? Probably. Something is being done now, however, and it's possible that e360 may find themselves right back at square one.