Should have updated the result really... after multiple reports, plus possibly the post here, its nice to say we beat this team. After initial reporting to CS when we matched, the top 10 in their alliance appeared to be banned quickly before war day started, and therefore were unable to attack. Further reports whittedly down the alliance to just 5 players who could make their attacks. We beat them pretty soundly as a result.
It was funny, if a little stressful, to watch some of their bases be upgraded from lvl 9 to lvl 113 in minutes... but I guess the Nexon gods were watching as the base then disappeared.
Its possible these players left of their own accord, but it looks like Nexon took quick action against this team and its right to say "well done" here when that happens.