One of the big advantages of being on here is that it's easy to talk directly to the people who run your server 🙂
If you want to contact your server's admin on Mastodon:
1. Go to your server's website
2. On the mobile web click ⋯ at the right, or on the desktop web click the higher "About" link on the left. Both of these will take you to your server's About page.
3. Your admin's Mastodon account is listed under "Administered by", and their public email address is under "Contact".