Do not question an Admin's perogative, end of story.
If you really feel a dire need to explain yourself though, approach the admin in a polite manner. Many players just say "stupid admin, listen for f**king once".
When I try to calmly, with all manners, talk to admins in PM about punishment and explain the story (OFCIOURSE IF IM SOMEHOW CONNECTED TO IT, not random punishments of others' players), they threaten me with ban and tell me that I'm not allowed to express my self. Exception was with Team_JayL.
I mean, what the fuck? When you might be right, you are still wrong? And who'd like to play with administrators like this?