What rights do I have for false noise complaints filed against me by the neighbor below, who has been very combatative?

I live with my wife and 13 month old son in a 1 bed + study apartment with wood floors and minimal sound proofing. That being the case, when my son walks, it does make some noise but nothing excessive. Since we moved in, the neighbor below has constantly banged on our floor regardless of whether we are making noise or not. We could be totally silent all day but if a spoon drops, the banging starts. Apparently, she works the night shift and sleeps during the day and is very angry if disturbed She has filed complains while my wife was sleeping and I was at work, and while neither of us we home. She has also filed a complaint about the TV, which we don't own. The apartment manager has said if the sound complaints don't stop we will be asked to leave. What can we do to defend ourselve