Possible Holdover Eviction

My landlord is trying to evict myself and my boyfriend, her cousin. She refused to do repairs to our apartment so we with held rent for one month and used the money to do some of the repairs ourselves. After repeated requests and a complaint to the dpeartment of Housing Preservation, she served us with a 30 day notice to vacate. In the notice, she claims the property is a four family home which is subject to mutliple dwelling regulations, and we have broken no rules or done anything to cause eviction. However, the property records and the NYS Finance records indicate that the property is a two family home. Does the fact that the notice claims other than the actual registration nullify the vacte order from the landlord? What else can we do? Any advice would be welcome.