Though I'm in rural Northern California, prime is really, really reliable, and 48 hours is the maximum - occasionally I get stuff next-day, typically I order late at night and it's there on the 2nd day (~40 hours). I had one instance where an item was marked as delivered, but I couldn't find it anywhere, so I contacted customer support, and they checked things out and sent me another item. 2 weeks later, the PO delivered the original, so I had 2, but Amazon didn't want one back. Another time, I'd ordered a 5# bag of organic cocoa powder (a few month's supply), and there was cocoa powder all over the inside of the box that came in. They shipped me another bag which came the next day, though I'd only told them to complain about the packaging (it was apparent that the cocoa bag had ruptured during shipment, so I was confident in eating the 98% which was still in the bag).
An interesting thing I've found, twice - I was shopping for chain, and found a 92' bucket of grade 30 5/16 chain, and ordered it - cost was something like $80 with free shipping (not prime). I was surprised at the price, as that chain would be more than $3/ft at my local hardware, so I watched the order page. They shipped it. I checked the item page, thinking "maybe I should get two buckets at that price..." and the price had doubled! -- Note, not an amazon product, different seller. More recently, I'd cut up that 5/16 chain for a few different uses, and decided I needed more (if you must know, I've found I can pull large blackberry patches out pretty effectively with a long chain - I use a long pole to shove the chain through a patch if the patch is too big to yank in one pull), and found some 3/8" grade 43 chain, at a similar price (75' bucket for about $90). Same thing happened; they shipped it and the price has doubled (in both cases, I did receive my chain). I do wonder what's going on with that, but it doesn't look nefarious at all. I have to wonder how much money those chain ordered cost the sellers, though, the 3/8" chain pail was 116#.