I totally sympathise. I heard about a block in Bondi where an owner who was clearly a bit off the planet would turn up at EC meetings and scream at all the owners … until one of them brought along a tenant who was a largish Scotsman with a black belt in something who would tell him to calm down.
You could spend your waking life plotting revenge – or just some way to restore balance – but that’s just another victory for his nibs. I’m not clear what it is that he’s doing wrong – is it just snooping and plotting? Or is he physically and/or verbally threatening. Either way, you should really consider an AVO as verbal assaults are still assaults under the law.
Or you temporarily take in a largish Scottish lodger (with a black belt).