The test of infrastructure is whether society would grind to a halt if it disappeared tomorrow. So let's assume as of midnight tonight, Amazon ceases to operate. What happens? It's annoying, but everyone just shops at a different place, probably in person because there isn't a great online competitor to Amazon (at least in the US). It's not a critical part of society the way power, water, roads, and the internet are.
All businesses make errors like this, the key is to push them to have better processes to deal with them, rather than outsourced and unhelpful customer support.