absentee landlord --what are my rights?

[fultonferry1]

I'm a renter in a brownstone with 3 apartments and one abandoned commercial space on the ground floor. For the past 4 years, I and the other tenants have been maintaining the building because my landlord won't. Cleaning the hallways, replacing hallway lightbulbs, maintaining the garbage area, shoveling the walkway, comissioning work on chimneys, general repairs, appliances, hot water heaters, gutters, buzzers, locks to fire doors, fire sprinkler systems in hallways, etc. In addition, since the commercial space has been abandoned for years, we've had no utility meter readings because no one can get into the basement. We've all sent multiple letters, left voice messages and no response. Up to now we've been taking this work off our rent and still no response. We're all fed up. A few days ago, construction started in the lot behind our building. The deck off the 1st floor apt. is on their site line and is going to be ripped down. Our cable and telephone wires run along this wall. We've called her and still no response.
We all want a reduction in rent and or the opption to buy the apartments. How do we aproach this issue since she's made it clear that this building is not a priority to her and we've been taking these responsibilities on for 4 years? What are our rights?