Here is a spot where the slab had to be cut to conform to existing conditions:
To pay that much and not even have a crew come out to measure first is pretty shoddy. I wish I could say you get what you pay for, but you paid premium for crap installation.
Also, when they were fabricating they called to tell me my sink I had purchased could only be top-mounted and I should 100% get an undermount so I did that and returned the original sink. For this and stellar measurement and installation, I tipped the two guys that installed $20 each and gave them another $20 to give to the fabricator guy for looking out for us. And that was still under what you paid and mine was two countertops and an island from one slab.