Amazon contract deliveries to organisations like Yodel, who you can't contact directly and have exactly the same problems with failing to deliver or chucking parcels over the fence etc.
Everytime I see my package is being delivered by Yodel I just sighs, they always find a way to fuck up an order.
But to be fair, it seems like Amazon, are no longer working with Yodel, I have not seen any item I have from bought from Amazon.co.uk to be delivered by Yodel for at least two years.