Refusing shipment from post office when left on door step

[nbxfan]

How does one go about refusing a shipment from the post office? My postman often tosses packages over the fence, or leaves them without ringing the bell etc.

Not that it is necessary to explain but, I made an online purchase and, got a notice that I was refunded for a part of the products I purchased. I called and asked them to cancel the order and, even though it has yet to ship, they say there is no way to cancel the order and to just refuse shipment...