Quoting some rules:
"NO SOCIAL MISTREATMENT OR ANNOYANCE
We prize for a fun enviroment for everybody, meaning all players should follow that philosophy If you dont wish to have your gameplay disrupted by a GM intervention, just play nice and avoid ruining the gameplay of your fellow players."
"This does not include playing according to game mechanics and game design like corpse camping in PvP enabled zones, which is not punishable."
So its not punishable to corpse camp people for hours, but you know, most of the times these guys are really immature and stupid so you could try telling them (if you have a toon on the oposite faction) something like "Hey I donated so you leave me alone!"
Then printscreen him saying dumb stuff about you donating or just donators in general and send to GM's to bann him for "Donor bashing."
Or you could tell him your colored or disabled and hes a racist or discriminating you by ganking you, try trigger them as much as you can, then printscreen and bann him for "Racism/Discriminatory Behavior"