Ninjalooting from an AFKer?

Hello,
I have been in dung yesterday, it was going quite well, except the thing that the TANK went AFK approximately in half of the dungeon, so I have switched talents to tanky, equiped my tanky gear and kept going (we didnt kick him) then, after like 8 minutes or so (the whole dung took like 15) he came back for final 3 mobs and last. We´ve killed the last and a ring for tanks dropped. As a DPS/TANK I needed it, as I didnt need a single roll the whole dung and as I was tanking half of the time I tought myself its OK when I need a tanky item. This guy started like "WTF??? are u serious? I´m gonna report you for ninja looting, etc." I was making fun of him, that he was afk and he blamed me for ninjing. Today I tried to log in the game and then I realised, that I am suspended for 4 and a half days, can we do anything about it?
(BTW I´d just like to add in the fact, that it wasn´t lvl 80 dung and that I am lvl 77, he was somewhere below me so he would change the neck for another in a short amount of time, so I think this suspension is totally off)
Thank you!

You were in the wrong. You qued as DPS, he as Tank. He went AFK so you should've kicked him and requed as Tank if you wanted tank gear. He was still tank and you were still DPS, regardless if you tanked trash or not.