What you need is a lawyer who does litigation. If you give Ben permission to give me your eMail address, I can contact you off-line and see what we can find. We have almost as many lawyers in NJ as we have diners, and badly marked roads! It also depends on where you are in the Garden State. I personally know lawyers who do criminal (like traffic or worse), real estate, personal estates and wills, adoptions, and labor law. But a lawyer who sues someone for you for non-performance of a contract (or defends you against it) is not one I've yet had to use. However, they aren't hard to find.

Unfortunately, I think it's messy. They didn't install the DE filter and didn't install the code drain for it. They installed an inadequate SWCG and stuck you with a Nature2 attachment (did you actually agree to Nature2?). The concrete deck is cracking and stained. The pool surfaces is stained. And the chemical advice they are giving you is (mostly) wrong and will cause algae.

Carl