" Inexperienced installer cut off too much of quartzite slab "

This was cut on site? Why was he cutting it on site? Is there more of the slab? How short is it as your pic is not clear?

It was precut by the fabricator but the installers cut it down on site to make it fit because they said it was too tight.
Now the fabricator saying all that they have to do is cut a new back splash & install it. They also used white chaulk on gray quartzite. The fabricator says they’ll change that out. Whatever happened to the days when the installer would measure, cut & install their counters?
Waiting to see when they are going to do this. Haven’t heard back.

Here’s a close up of the seam between backsplash & slab