I too have been reamed by the pro's I trusted for several years to get my system fixed. In fact they were screwing it up more and more while telling me it was time to start thinking about getting a new one. Four years later, consumer educated, both coils cleaned and 3 extra pounds of R-22 removed, my old heat pump now works GREAT.
Legal claims are unlikely because there are many ways and reasons to argue their incompetence/malfeasance, plus a lot of time has passed. So, I will no proceed to do the most important thing I can do as a consumer- trash their name to everyone who can listen.
Anyone reading this, feel free to contact me for the name of a contractor NOT to use in Central Maryland.