It occurred to me that I might have given the impression that the situation with the neighbors is more grave than it really is.
1. We knew moving in that there was the possibility that we would have to get carpeting if the neighbors complained about the noise.
2. We do not have to carpet the apartment wall to wall - just 80%.
3. We were advised that no further action at this point was necessary because the neighbors did not complain in writing. Speaking with the neighbors at this point would be premature. They have to get use to us. We have to get used to living on the fourth floor as opposed to living in a first floor apartment where there are no downstairs neighbors.
4. We haven't heard any knocking since last week.
5. Worse comes to worse we put some carpeting down or spread out some throw rugs, which is something we were considering anyway. It's not the end of the world.
Thank you to my friends for your advice and your concern but this is not what I would consider a serious problem. Although, I did appreciate the opportunity to vent.