I would ask for a lot more money to finish the job (a lot more) and say "take it or leave it". If he isn't willing to pay the extra money, I would just walk aw

I would ask for a lot more money to finish the job (a lot more) and say "take it or leave it". If he isn't willing to pay the extra money, I would just walk away. There's nothing to be gained from debating with a troublesome manager who doesn't understand programming. You would just be wasting your time.