I once had a parcel not delivered because "the driver couldn't find your address". I had called the delivery office because the delivery was overdue, and this was the answer I got from them. If I hadn't called it would have been returned to the sender.
My house is directly behind the road name sign with the number in 4" high characters on the wall.
I suggested that perhaps postal vans should be equipped with an A to Z.
I another instance a parcel from USA was not delivered and we didn't have a card left despite the fact that we were at home on the day they said they had attempted delivery. The result was that he parcel was returned to the sender and cost them another $26.00 on top of the original postage.