The subject of this poem actually is the conflict between the two voices. The speaker is "Madame" and she is in conflict with "the Rent Man." He is there to collect rent but she refuses to pay. Several problems exist in the apartment, including broken sink, squeaky floor, rats, and leaks. Madame is angry that things have not been fixed, but the real problem lies in the fact that the "Rent Man" is not actually the one responsible for fixing anything. He's simply there to collect the money. The real problem is that Madame's complaints are not even reaching the right person, or if they are, nothing is being done and she is powerless.
Likely this is a picture of a common situation that speaks honestly and ironically of a bigger picture issue: the inability of blacks and whites to communicate because whites were unwilling to listen.