# email.complained: they said spam, believe them
The email was successfully delivered, but the recipient marked it as spam. This is the most reputation-expensive event in the catalog.
## What to do on receipt
1. Unsubscribe the address immediately, everywhere, not just the list that sent it. Never email them again without explicit re-consent.
2. Check your suppression list: Resend adds complained addresses automatically. Do not remove them.
3. Review what you sent: was it expected? Was unsubscribing hard to find? Did you mail someone who never opted in? A complaint is a content and consent problem, not a technical one.
4. Watch your complaint rate. Providers start filtering you aggressively well before you think the rate is high.
## The trap
Re-mailing a complainer "to confirm the unsubscribe" or arguing with the signal. Every additional send to someone who complained compounds the reputation damage. The other trap is treating complaints as bounces to be retried. A complaint is a human saying stop; the only correct response is to stop.