Lemme quote those Ts & Cs... "any contract to sell and buy Products is made only between the Seller and Customer concerned and NOTHS is not a party to any such contract"
Some friends of mine have a web business with a monthly membership fee. They use a payment provider to handle all the payments. Your logic has the customer's only contract being with the payment provider, not the actual website. Don't be daft.
Really? Amazon themselves come to your house with the package?
I thought Amazon were the delivery company...? Yes, your contract is with Amazon, in that instance, and it is Amazon who are responsible for kicking the courier. But if you'd bought _through_ Amazon, your contract would be with the supplier, not Amazon, and it would be the supplier who would be responsible for kicking the courier, not Amazon.