> We got 90-95% finished with the problem. The issue is the last 5-10% is many, many, many orders of magnitude harder than the other part.

That's one of the reasons I got out of the webdeveloper freelancer market. Certain people would hunt big projects, do "90%" of them and take most of the time and money when suddenly their cat/relative etc would get sick or worse. The guy who posted the original job would repost the job stating that I have a website that's almost done, I just need a few changes. Those few changes were 95% of the time and skill required for completing the job. Plus the job is extremely competitive these days, with sometimes hundreds of individuals applying for a project.