In my case, I had something like a 50% failure rate of Prime delivery orders. It was at the point that every time I'd buy something with a delivery date of tomorrow, I'd get it 3 days later after it was dispatched from Germany instead. The drivers who did turn up have now been banned from delivering to our apartment block, as they would ditch all the parcels outside or with security instead of delivering them. Standard customer support wouldn't refund my Prime subscription because I had apparently used it 66 times in 3 months, which must mean that they must count MP3 plays as uses, as I only ordered 12 parcels in that time. Thankfully I did eventually get hold of someone who took the time to check and see that I've been buying from Amazon since they launched in the UK, and had been a Prime member since that launched too, and she promptly refunded me the membership. It took far, far too many managers to get to that point, however.
The general customer service seems to have deteriorated in the past year. Prior to that I always had great customer service from Amazon. I've now largely switched away to ordering from elsewhere. eBuyer gets me my parcels within a day on free shipping, and they're pretty competitive on price. I always ordered from Amazon because the CS was good, but they've lost me as a customer for now.
Must be a cost-saving initiative in their support org. I've never seen a retailer that could even properly bucket losses into "our fuckup", "possibly our fuckup" and "satiating customer." And forget about always fixing things when they are recognized as a fuckup. There is too much incentive to not to do anything for the customer. Even when its the "right thing to do." Metrics often prioritize short term savings over burning a large-but-not-VIP customer.
I once worked with a retailer where even their Point of Sale voids were bucketed wrong. If a CSR were to accidentally scan the same $X item twice, they would void one on the POS. The stock control logic would keep the product in inventory counts, but the end-of-day financial tallies would look the same as if they manually applied a $X discount on an order.
I don't mean to imply Amazon is _that_ bad. But just because they're a big software employer, and AWS is a decent product, it doesn't mean that the support staff, internal software, etc... aren't shite.