There are several routes to resolution when a repair is needed. The right one often depends on your relationship with your landlord.
According to Andrew Wagner, "write a letter demanding that they repair or replace it. If they ignore your request, you could withhold a portion of your rent until the problem is resolved, arguing that the problem violates the warranty of habitability, a state law, according to Andrew J. Wagner, a real estate lawyer in the New York City office of the law firm Anderson Kill. But your landlord would probably take you to housing court over unpaid rent. Alternatively, you could call 311 and request an inspection by the Department of Housing Preservation and Development, which enforces housing-code rules and could issue the co-op a violation. Your outlet may or may not get repaired, but your relationship with your landlord will probably be damaged."