How does the deal between Levene and Williamson fall apart in the novel, Glengarry, Glen Ross?

After Levene and Williamson set the conditions for the leads, Levene says he wants two sits that night. For a moment, neither man does anything, and then Williamson prompts him to give him the hundred dollar fee. Levene does not have the money, and Williamson will not take an IOU. Moreover, Williamson refuses to split the two leads and give Levene one. The deal falls apart.