The way I worked with my GC is I paid him half after the demo and the other half upon successful completion. This was my only experience working with one, so I can't speak to what is the usual arrangement. He proposed this, it seemed fair, so I agreed. Given that you have paid in full for work that is unsatisfactory, I would propose to him two options: 1) he make the job good at his expense 2) you make the job good at your expense and see him in court. You may choose to negotiate to whatever resolution YOU think is fair, but if it were me, I'd say "your choice" and follow through. You DO have a contract with this GC, I presume. Good luck!

I am not sure how the vinegar would change the grout color - probably not. I've used vinegar to help remove grout haze from tiles and if haze is what is causing the grout to look different colors it is worth trying. There is such a thing as grout paint which can be applied to the grout to make it all one color.

Here are

The color that we chose is supposed to be the lighter shade u can in the pics.