Earlier quoted context omitted.
Amazon SES — $0.10 per 1000 emails.
Because it's shite. I've blocked SES's IP range on all my servers, as they just ignore spam reports.
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...