Answers

A lawyer is the first place to start. Your builder should be insured for problems like this. If it is a big box builder then I am sure something in the corporate contract has an answer for this. You definitely will want to keep any paperwork, emails, texts, etc just to back up your claim. Also the city/county should have the design on file because that is what the permit is attached too. 

http://www.houselogic.com/home-advice/tax-credits/how-to-collect-tax-energy-credits/

I do not believe that would qualify. Only the materials qaulifies for the credit.