4 years ago I rented an apartment on the 1st floor in 2 family house on month to month basis. I wasn't aware that there was an illegal basement apartment in the building. We had a multiple problems when living there including rads, bed bugs, no hot water etc. We decided to move out 2 months ago. A friend of mine who is a licensed attorney just advised me that since there was an illegal basement in the building the landlord had no right to collect the rent from us for the entire time we lived there. Can i sue the landlord for all the rent I paid him? The family who lived in illegal basement moved out a month ago but I could prove that they lived there during my occupancy. Please advise.