What is the main point of contention between Matigari and Williams in the novel, Matigari?

The house where Settler Williams once lived and where his son Robert and servant John Boy now live is one of the main settings of the novel, as well as the central point of conflict between the Williams and Matigari. The house is large and, according to Matigari, belongs to him and his family. However, because Matigari has no title deed to the house, Robert and John Boy refuse to part with the house. Settler Williams is killed in the house.