Sorry to hear about that experience. One of SES's primary goals was keeping abuse off of the service, though no system is perfect. When I worked on SES, more than 50% of the team's total time went into fighting abuse. Part of that effort was comprehensive monitoring of a variety of feedback signals, including bounces, spam complaints, and other data. Individual senders are encouraged to monitor their own sending via the Reputation Dashboard and related facilities [1].

SES also monitors these signals, and if it detects signs of abuse, such as elevated bounces or spam complaints, then a sender's ability to send may be paused and the account's activity may be reviewed. FAQ on these processes [2]. Some of the tolerates are quite tight, and can result in action being taken even if much less than a percent of messages are getting these sorts of responses. There's a lot more that I can't describe in a short comment.

SES processes and reacts to spam reports sent in standard formats like the Abuse Reporting Format (ARF), and looks at signals like List-Unsubscribe and bounces, etc. But this does require the system to understand the format of the reports used by the feedback loops [3]. Do you happen to know if your feedback loop sent spam complaints in ARF format? If you'd like to discuss further, feel free to reach out to me directly.

[1] https://aws.amazon.com/blogs/messaging-and-targeting/announc...

[2] https://docs.aws.amazon.com/ses/latest/DeveloperGuide/e-faq....

[3] https://aws.amazon.com/blogs/messaging-and-targeting/email-d...

It's not actually SES' responsibility, the sender can use SQS to receive bounceback/spam notifications and act on it.