Saying that we haven't heard from them is just a lie. We got an answer in this very thread:
We also got a statement on their twitter:
https://imgur.com/a/IT8ew
Lastly we had lengthy responses from Suzerain on Reddit:
https://www.reddit.com/r/ElysiumProject/comments/5lf6ky/is_this_really_what_has_become_of_nostalrius/dbv7qbi/?context=3&st=ixkfda7l&sh=7849816a
From these responses it's quite clear that it's not within their control. What is their interest in not solving this problem, if they were able to? They are getting a lot of negative players and publicity, so it's hardly just a means to keep server numbers down.
It's obviously not as 'simple' as just fixing it. Neither does it mean that they lied, when they promised people would get their characters back. Getting the data has always been on Nostalrius' terms, and as such they don't control it as much as people believe.
People disregard the legal problems in this matter. Blizzard obviously still have a firm grab around Nostalrius' balls - otherwise they might as well have remade the server themselves. They must've believed that the character transfer wouldn't cause any legal problems with Blizzard (or choose to disregard them for a short term), but this has clearly changed. All of a sudden Nostalrius has almost evaporated. Does this seem like something Nostalrius would do without a reason? Probably not.
Our best hope is that whoever is sitting on all that data had a serious problem with the servers, and that he/she is trying to fix it. It seems like a long shot, as something like this would probably have been communicated to people. No, the silence from Nostalrius makes me believe that legal matters are to blame. This would also explain why Elysium is not coming out with a more clear message on the matter; they know Nostalrius is caught up in legal problems, and making it public would only make matters worse for Nostalrius. Being respectful of Nostalrius they avoid addressing the cause of the issue instead.