no heat in apartment

My friend has been complaining to her landlord that she doesn't have heat. It's an old bldg & she has cheap rent, but there are several units in her bldg that don't get heat - because of the pipes, many units do get heat, just a few don't. The landlord has tried to fix the problem, but so far nothing has worked. She can see her breath, it's that cold. I've told her to up her complaint to the rental tenancy board, but she's worried about putting an official complaint as she's lived there for years (heat in the winter has always been an issue) and she can't afford to move elsewhere. 

Is there somewhere she can contact for immediate action?