I know in the lease agreement I signed it states that all persons residing in/on the property for greater than thirty days must be added to the lease. If I had rented out a room without the landlords knowledge I would receive no help from the landlord in removing the problem renter and could face some repercussions myself for violating my lease agreement. You should take a look at your lease agreement and read it carefully to see if that was included. If it is not included you should be able to get help from your landlord.