delete the email pool that is ready to send.

I use SES to send emails via SMTP. I got many complaints, so I checked my dashboard and found 50000 emails in the queue to send, which is not us. Immediately deactivated my credential, but I cannot delete the email pool that is ready to send. I checked the documents, and all mentioned the queue should be in SQS, but it's empty. The first question is how we can delete the ready-to-send emails. Second I've already activated DKIM and DMARC. What can I do to prevent that?