What a pain. Back when they started threatening to "upgrade" and close the old site, I had exchanged a few emails with one of their online-community-managers or whatever, arguing to keep the old site around, at least as a read-only archive. I will contact them again , I recommend multiple people do the same. Hopefully they didn't perma-delete everything yet.
I had also tried real hard to wget / curl / scrape the old forum, but they had very aggressive clownflare settings that kept denying everything. Wasted a bunch of time for no result.