Great case to make that you are so incompetent as a broker-dealer that someone was able to extend themselves 250x leverage on the margin you extended. That's how you lose your broker-dealer license, which means your business dies if you're Robinhood (unless they're only going to offer a cash management account, which I guess might be a thing? even Credit Karma and Personal Capital are offering one now). As a broker, risk management is your job.