Yeah i know, it's awful...But there's nothing much you can do now besides leaving him negative iTrader. It's not pointless. You never know if it was a temporary or definitive ban. If it was a temporary he can return to DP and last time i checked he had 4 all positive iTraders... I don't know how he is now though.
I'm sorry about your loss man. I hope people will learn something from your experience. Move on and keep up the good work. Money comes and goes. Look it as if you've bought a $900 phone and lost it.
Never transfer by bank deposit or western union someone you don't know If you do deposit by bank, do it from ebay provided he has a better reputation