Palustris...it seems my problem is quite different to yours.
The difficulty I am having is the postcode is too vague, and not specific enough. But yours seems to reside with Amazon.
Your postcode contains everything that the driver needs to get to within a few yards of your house. In addition, Amazon have your telephone number to help them, which they mysteriously refuse to use.
I don't use Amazon, for reasons that might not be appropriate to discuss on this thread. But you see to have come across another perfectly good reason not to use them.
I have used Ebay on numerous occasions over the last few years, and rarely encountered any problems, mainly because most sellers use Royal Mail to deliver, not couriers, which seem to be Amazons chosen method. I have never, ever had any problem with the Royal Mail....their posties are quite the best that it is possible to get.
I suggest that you use ebay from now on.