Facebook isn't archiving my data! Now what?

[Jessica]

I have over 121,000 messages from a conversation I'm trying to download. I used Facebook's data archive feature to download a copy of my Facebook data - and it gave me everything BUT my messages (the page where messages were supposed to be said there was an error and they were looking into it).
So I tried archiving my data again. Facebook sent me the "we're getting your data ready!" email, but never sent me the email to download it. When I checked back a little later, my data wasn't ready - it had never been compiled, and the green "start my archive" button was back! So I tried it again. Again, initial email, but no follow-up, and it reset itself again. Facebook has nothing about this in their "Help" center (feel free to use air quotes on that).
Those 121+K messages are important to me. I've tried using m.facebook.com and resetting the link's view values, which is the only other way I've seen, but that hasn't worked - and there's too many messages to do it manually anyway; it would crash my poor little Macbook. XD
If anybody has any advice about Facebook archiving, if it's doing this to anybody else, how to fix this, etc... it's been over a month I've been trying to download these messages, please help. XD