If you’re providing email service, you should be actively monitoring public blacklists, not waiting for your registrar or hosting company to notify you. Even if your domain isn’t banned, your users’ emails may be bounced by other servers. That you don’t seem to know any of this means you aren’t employing the right people.
>>Svexax+(OP)
I'm pretty sure you're over inferring stuff from that post. It's not credible that 20+ years old company serving email for millions of users wouldn't know the most basic stuff about running an email server, don't you think?