Your LL is under no obligation to rent to you at the same rate as the other units. Each unit is different, for example unit A may have new carpeting and faces the east while unit be faces the south and has older carpeting. The lanlord can rent for whatever he feels is reasonable for his unit. You can decide to move if the rate of rent is unacceptable. As for your present problem, unless your are given proper notice go by what's on your lease. Familial discrimination is against the law.