There was a post I made miles back in this thread somewhere...
When I had my 4S delivered, I had two orders go through during the chaos of trying to order one. I kept it open though as a family member wanted it. When UPS delivered, the guy had one phone, I explained I was expecting two to be delivered. He didn't think that was the case, so went back to check the van, discovered there was another one and came back with it.
So perhaps it was missed because he thought he had delivered to you?
i was just told to wait 24 hours