what strategys to use against people who c-bet to much and not enough ?

On c-betting too much: If your opponent playing a weak range aggressively, you should adjust by re-aggressing him with air more, calling him for value looser, and be more inclined to slow play.

On c-betting not enough: If your opponent is playing a strong range less aggressively than he should, you should adjust by... depends what you mean. If this means his range for aggression is even tighter, you should do the opposite of everything I said above.