I agree, it sucks.. But in all fairness, if you are refering to a dealer there is NO real anticipation of when a part will be delivered.. All they can normally tell you is if it is in stock and normally arrives within a couple of days..
If something is backordered or unavailible in the local warehouse, there's no way in they can rub a crystal ball and tell you it will arrive in three weeks.. Would you rather have a guess of an answer and then be even more upset when it isn't there as scheduled??