But do you have a copy of the lease? How is he in breach? hhe conditions and probably consequences if there is a breach, will be governed by the lease agreement. By consequences I mean if there is a dispute, it may require arbitration, specify a court, or even require that the losing party pay attorney fees and costs.
Did you pay by check? If so you should go to our bank and get copies of the cancelled checks. Do not rely on the other party to get all your evidence. Also depending on the value of what is in controvery and what is in the contract you may be able to go to small claims if it is less than $5,000.