They end, and no money is taken from donors, and the company gets no funding. So the pledged money is safe.
On a practical level many projects either refine the offer and try again like on KS or they find another way to fund themselves, and sometimes they just drop the project.
As for the WoFi, i’d say there is almost no way now that it won’t hit target. They are so far along , 80% of the way, and there are 23 days left. There is always a rush at the end, for whatever reason, and that will definitely push it over the top. I’ve watched a lot of these through the funding so i know how things have worked in the past.