Poor installation workmanship

How do I complain about unacctptable installation workmanship and, more importantly, get something done about it? I finally took the bait and let them upgrade me to fiber. As if it wasn't annoying enough that this upgrade now requires TWO boxes that both require power, the under-house work was totally shoddy and UNACCEPTABLE. A real professional would have attached this cable to the bottom of my floor joists, snaking it over the other things, like HVAC ducts, that hang below. But, NO! This guy string the cable from one place to the other, with no strain relief or anything, letting it dangle where it may. I'm sure if I was to accidentally catch this on something while working under there and damage it, they'd want to charge me for the repair (and possibly do another crappy job with it). Do I now have to crawl under my house with these people to make sure they do the job properly?