10 years ago, this was a lot of data. It isn't anymore and it makes it that much more bizarre that they're having that much trouble getting it back. It would be less to just give them access and let them download it themselves and perhaps stick it somewhere else temporarily than to pay lawyers to deal with legal filings.
To put it in vaguely physical terms, what once was a university library is now a good solid bookshelf full of stuff. Legally wrangling over a huge library is one thing, but if it's just a bookshelf, metaphorically, let them come in for an hour and clean it out themselves rather than bringing in the law. Obviously not a perfect metaphor on data size, this is more about how lawsuits are more of a hassle then just giving it to them.