We need to know how to deal with overzealous mods

I have this one player in particular that always insults me, calls me this or that name, accuses of everything under the sun. I have reported this player time and time again. Constantly this player gets only temporary bans...oh well I have no control over that, though I know the powers that be should do more than temporarily ban them. Now comes to today, an overzealous mod jumps in after I was receiving this abuse, all the while I am being polite, as is possible, and hits me with a ban. I'm sorry, but I am not only being victimized by this player but now by this mod. In my eyes this mod may have authority, but they have lost the right to have any respect.

What I want to know is how to formally file a greivance against this mod.