Bulk Mail Newsletters Solution Needed

We have a laravel app where allow multiple users to create subscribers list and they can send mail to their subscribers from the laravel app itself. We are hitting a small monthly number right now around 5K but we are expecting to go upto 100K soon so we don't want to use existing server to send mails or to use any other platform like mailchimp because of the cost mainly. I am looking for a cheap way to send emails like AWS SES for 1$ it sends 10,000 emails. Few Important Concerns 1) Since there are multiple unknown users how do we know which user sends spam mails so we can remove him from the platform 2) How to prevent the damage if anyone sends the spam people it shouldn't affect our reputation or get us blocked? If you are with me still write Email on top of your proposal Note: Laravel app is already done just need to switch to a cheap good email provider.