Sometimes, there is an article saying you cannot fire your PM. Although it sounds ridiculous. Second, if you can fire PM, check under what situations you can fire PM, and what is the cost to fire PM. Usually it associates with a large amount of money. Like you pay him next three months's management fee. Although it sounds ridiculous. But those are not rare; I am a owner of a PM company.
Then assess if you want to pay PM the amount. If you do, then write PM a letter saying so. Be brave to confront the PM face to face, and don't be a chicken. Make clear PM is fired and you will report the behavior to the realtor board.
Last advise, if the RE is not something that in yout plate, quit. Not only there are bas tenants, but also there are thug PMs. Hoho.
