Earlier quoted context omitted.
Reason #99,999 that I don't use Amazon anymore. Just buy stuff in-person, pay the shipping, wait the week, or whatever. You'll be fine I promise.
Stuff in person costs 2X the price though. Especially bike parts. It's often cheaper to buy from Amazon but never go through troubleshooting support. Always return or replace. If that doesn't work, give a 1 star review, wait for the seller to come chasing you with a gift card in return for 5 stars. Change it to 5 stars, spend the gift card, and then change it back to 1 star.
The thing with bikes and bike parts is, details matter, two seemingly similar looking parts might be completely different, and there are many small parts that have many options (length, material, color, thread type etc). So unless you really know what you are doing, it's very easy to mix things up - that is true for the consumer too, of course :) Any non-bike-specific webshop is doomed for this reason, except for some special items, eg. eletronics.
One thing I noticed is that these days there are more and more small shops that are legit online, they may not be offering small parts, but I bought a bike from one such shop 2 years ago, and it was heavily discounted, the bike was exactly what they said it would be, it was in stock and was shipped within a week to another EU country no problems.