If someone is harassing or abusing people, shut them down, by all means. And if someone is breaking your server's rules about commercial activity, report them to your moderators, of course.
But if someone is doing no harm, but just posting things you don't want to see, just unfollow them. And if they keep showing up in your timeline, block them. You'll both be happier.
If you have a fediverse account, you can quote this note from your own instance. Search https://cosocial.ca/users/evan/statuses/114485843232427899 on your instance and quote it. (Note that quoting is not supported in Mastodon.)