When one of my shipments was late and "fell of the radar for three days" I contacted them and told them that I was concerned that it's lost in their facility...
They posted update later that day and it arrived two days later...
Sometimes you need to push it through... I told them if I waited too long to contact them, it could have gotten more lost than if it just fell off a conveyor and they didn't catch it... That way they can send someone to look for it...