A long time ago I had issues with a horrendous re-roofing job that I ended up taking the contractor to court over. As part of the case the local building control department helped by sticking their oar in, as did the technical department of the tile manufacturer, both calling the job a crock..
Incidentally I won, he transferred his assets to his wife, folded his co and set up again the next day, I got nothing.. but that's by the by and par for the course; main point is if you want to take someone to task, there are various options for professional opinions available as input on the quality of the job