If you have a complaint about the construction of your new home, you should contact your builder and/or the warranty company (if any) to resolve it. You should also contact your lender who has a responsibility to help you resolve issues related to new construction. Your correspondence should be in writing and you should keep records regarding your attempts to resolve the issue. If the lender is unable to resolve the matter, the lender should refer the complaint to HUD for further processing and so advise you. Any questions related to this issue should be addressed with your FHA lender.
Handbook 4070.1 https://www.hud.gov/program_offices/administration/hudclips/handbooks/hsgh