Yeah you got shafted alright. Best bed is to build a case up against him (receipts vs what he's actually done, which means getting another professional to look at your). It's going to get pretty tough for you now man. Hopefully he's less of a dick to you the second time round and actually fixes the issues. But that won't happen, because if he was like that, you wouldn't have issues in the first place!
Perhaps look into Fair Trading, maybe ask someone in your state if they know someone who can give you advice on this matter.