A couple of senior citizens who have been living in the same San Francisco apartment for almost 40 years discovered that their landlord had been ripping them off. After achieving a negotiated settlement with the landlord, the couple quickly found the landlord retaliating. This is unconscionable evil.
Rent control laws exist to protect people from exactly this type of situation, while California's notorious 1985 "Ellis Act" was presented as a way to let landlords take housing out of the rent-controlled market, it is far too frequently utilized as a tool to terrorize tenants. I think there are tenant rights lawyers who specialize by neighborhood in San Francisco, Santa Monica, and Los Angeles.