wouldn't that be harassment from the tenant below if they are banging your door to a point of obsession? especially since they do it on purpose? sue them for noise disturbance. it's not your fault the floor is old. it's different for you vs. them. they making the noise on purpose. your noise is just due to environment. passive noise vs. active noise.
rugs or carpeting might help if the floors were totally bare wood. see if you can get the owner of the building to pay for installation of noise canceling floors if you live in an apartment.
