[Plugin: Woocommerce] Product decrease when order is processing / completed

I am using woocommerce now, currently running an online digital store. So I’ve been having tons of trouble customer submitting order and don’t buy.. This messed up my product stock count as they decrease whenever they get order. Been looking for quite sometime now but i haven’t able to get any answer. Can anyone help me? I need to product to decrease when the order status is in processing / completed, not on hold 😉
Thanks! Your help would be much appreciated ! 🙂