Refused to sign rent agreement renewal and vacated immediately

Hi, My tenant was agreed to renewal the rental agreement for next 11 months for same rent (which one due on 08.05.17) and sent his acceptance twice in Whatapps. I believe him, prepared renewal agreement and ask him to sign on 09.05.17, but he refused to sign and got vacated flat on 15.05.17 (just one week notice) without sign the renewal agreement. He said agreement gets over on 08.05.17 and don't have right to push me sign for renewal and ask me to return advance after deducting unpaid rent 01.04.17 to 15.05.17 and holding the key. Shall i adjust unpaid rent and rest of notice period, total 3 month rent (i.e Apr to Jun) from advance based on his acceptance of renewal since notice period is 2 month as per agreement. Kindly advice on deduction amount and can take legal action against him for dishonest and illegal overstayed without signing renewal agreement. What is purpose of make rent agreement and notice period if tenant vacated flat after lease period without signing renewal even they agreed before it get expired. What are the legal steps that can be taken by landlord against tenant. Thanks.