Yeah, the promise is still Adventure Mode. I don't expect to be paying again for the Economic expansion should that goal be met at a later date. Rereading the original Kickstarter, it does seem like they failed to provide a promised feature, and various Muse posts recognize that it was their bad. My original question was about how they're handling that.
I understand you guys are trying to be helpful but I really think this is something only the Muse team or those that have requested a refund or some other solution can answer.
EDIT: From the Muse Kickstarter comments, by Muse: "If we can't raise that as part of this Kickstarter, you will get a Season Pass to all the DLC we will release along the way to Adventure Mode feature complete. You will still get Adventure Mode at some point, it just won't be in one big DLC as we'd like it to. That's just how we have to structure it being indie devs." So yes, heart attack over, you're definitely getting what's been promised to you.