Unless it was an extreme account of racial slurs and just down right verbal abuse nothing would be done. It is their private room in which they can run how they choose (to an extent of-course).
If you feel that, however, they have offended you enough to account for a punishment send a pm to a GameMaster along with the link to the screenshot you took.
But my honest advice to you is just leave it alone and grow some thicker skin. It's the internet.