I will go on to say that this remains a generally unsolved problem for companies working at scale that are under scrutiny and dealing with financial or social fraud. They are willing to accept false negatives instead of false positives.
I worked in an organization that prided itself with great customer service, and they did deliver. The cost of doing so (resolving each case manually, often giving benefit to the customer) is significant.
Amazon is another prime example of a company that does customer service well - though that might have some consequences on their work culture (mistakes are not easily forgiven - since the cost is so high). Not an apples to apples comparison though, Twitter is ad based (much higher volume/users needed for revenue) unlike Amazon.
More users = more challenges with the same level of staff. That’s how you end up with a cheap processes (lots of automation, outsourced reviews) designed to handle 90% cases vs. an expensive/more thorough process (manual checks by experts along the way) that can handle 99% cases.