Are they also posting with your account? That would explain some misunderstandings.
Maybe they should register themselves and participate in the community?
I agree with the others.
1. Server owner/host sets the rules and delegates supervising them to some administrators.
2. Administrators are volunteers and players alike. They do mistakes as well and they are not always right. But in general they are equipped with special rights to fulfill their "job". That's more a responsibility than a reward or superpower.
Remember they are also and mainly players who want to play. Every request should be considered if it's necessary or just bothering them.
3. Players need to follow the server rules. And admin and owner requests. If these requests are violating server rules either contact the owner ingame or leave the server, if you disagree.
4. Visitors have to behave.