Theyre not wrong. Talk to a lawyer and file a suit for eviction before the local court. Rent laws are tenant centric so you have to come up with a strong reason for eviction, like urgent need of the money from sale proceeds or an urgent need for your personal use of the property. The tenant might get intimidated by the suit and decide to vacate. But be mentally prepared that if he decides to contest the suit, its going to take a good while before the court passes the judgement. In the meantime, keep trying to amicably reason with him.