Sounds like they didn't want to buy any fill dirt & dilute their profits. No big deal, filling low spots isn't too difficult. Are you willing to level it yourself or are you looking for some kind of leverage to get the contractor back out to do it?

It's mainly for leverage, although these were college kids that did it for cheap so no big loss. I also wanted to make sure I'm not missing something.

Well...You're missing some dirt but that's about it!

Yeah it is def low as you can see the sprinkler head sticking up, that should be at its highest level with the top of the dirt.

If the sod has not knit down to the underlying soil, pick it up and drop enough soil to get it where you want it. If the roots are already moved into the soil, then take a flat ended shovel, dig under the turf roots to get the entire turf, and put the soil underneath.