If I understand everything correctly in ch. 86 Thomas (whoever that was again) acted as a mediator between Toru and the lord in getting him the house, so either it belonged to the lord all along and the sales guild just sold it anyway, though they had no right to the place, or they sold it twice, to Lily, known to be the town's most powerful magician, nicknamed Infinite, and for her bad temper when angry (chapters 20-22 and 73), and the feudal lord, a noble.
What was the plan here? How did they ever think this could not backfire? Are they tired of having a head on their necks?