I have contacted support and they point me back to the forums and say wait for a patch, which I assume is never going to come at this point considering the age of the game. Really disappointing. Other threads appear to have been resolved through a "rewind" of progress to an older date which my support agent said they couldn't do.
Honestly it would at least be preferable to just have all my progress properly wiped at this point, if I'm leveling everyone up from scratch might as well clear my milestones too so I can re-earn them...