My aunt has a tenant that refuses to pay rent.By the way we live in nyc queens. Is been a month already that the tenant doesn't pay rent. According to the tenant, the tenant has the right to live for free for at least two months wich the court allows. There is no lease written wich I guess falls into a month to month basis. She is planning to take the tenant to court ( She alredy served her with a paper asking for the rent or vacate in a return receipt letter). My only concern is that the property where they live has a CO (Certificate of occupancy) of one family and my aunt modified the structure to a 2 family dwelling. The apartment that the tenants use has not been modified at all. My aunt made an extention of the house and thats were she lives. Can the tenant claim in court that the building does'nt have the proper CO and therefore unproper for people to live there and nevertheless and more important my aunt can't charge rent. What is her best approach to this dilemma.