First we have to determine if it is a legal apartment....
You could also assume the landlord is too cheap to have 3 meters put in since he would have to pay for it...it could be a legal 3 family.
But if it is an illegal 3, the landlord would have to evcit you in Supreme court NOT housing court...Dont let him tell you different....and that could take months and is not cheap for him...
So you are probably getting ripped off for the electricty, since you have a smaller apartment, and yes you can report him to the zoning board, and he will get fined and either evict or make it legal,
But for you to withold the rent, you have to get the certificate of Occupancy, from the buildings dept,and see how the house is zoned, if it is zoned 2 family and you are in the basement then it is illegal, and you can withold the rent, BUT you cannot get back rent.....
Unless a judge says so, and with a signed lease that proves the Landlord Knew all along it was Illegal.
As opposed to month to month, paying the landlord in CASH or money oders, and refusing to give you a lease....no records etc...then that should have alerted your red flags to it being illegal.
But with a lease, the landlord is really screwed because a lease entitles you to rent a LEGAL apartment!