Can a PM take part of my security deposit?

[Mark Stevenson]

My PM just evicted 2 tenants in a 4 plex. They were going to charge too much for the cleaning and make ready, so I asked if I could do it myself, and then they could send me the security deposits. They said yes - both tenants were thousands of dollars behind so neither tenant would get anything back. I just saw on my monthly statement they charged me an 8% fee. When I asked they pointed me to the PMA that states they charge on "all gross receipts" and then said: "Our interpretation is coming from the IRS. The crucial part is “all sources” and that is why security deposits are also considered."

My question: Is this a thing? Do I really have to pay 8% of the security deposit to the PM? 

Note: I "can't" change to a different PM. I tried. They are the builders, and the PM and the HOA - and there is an HOA bylaw that states that the same PM has to manage all the 4plexes in the entire community. Thus creating a monopoly that I don't know how to get out of.