This is truly a sad situation.
Being a dinosaur, I try to not order large dollar items directly over the internet. I'll call their customer service on a POTS line and verbally place the order. In that isn't an option, I would wonder about the outfit themselves. If they can't have someone answer the phone to take orders, can I really expect good service?
While on the phone, I'll get the persons name with whom I'm placing the order and have them verify that it's CURRENTLY in stock and ready to ship. If either is no, then I didn't want it that bad.
This can be done in a non-confrontational way and, so far, it's worked fine but, of course, this assumes the person on the other end is honest.