Tenant not paying rent or vcacating my apartment

Hello Sir, My tenant has been staying in my apartment for 5 years now (Hyderabad), on rent. Initially for 3 years, there was 11 month rental agreement, which we signed. For the last 2 years, due to some family emergency, I was unable to get the agreement renewed. One month back, when I asked him to sign for the new rental agreement, he mentioned that he will vacate the house within a month and thus he doesn't want to sign an agreement. I searched a new tenant and they are ready to sign agreement and occupy my apartment for rent, but the previous tenant who has been staying w/o rental agrrement for 2 years now is delaying his moveout saying that he cannot find any other place to stay. He has stopped paying rent for the past 2 months asking me to deduct the same from security deposit (3 month rent) that he paid before entering the house 5 year back. Question: 1) The existing tenant is not paying rent and also not vacating to the new tenant. So what can I do, as I don't have a recent agreement? 2) On a current date stamp paper (01-Oct-19), can I get an agreement made, mentioning signature date on stamp paper date (01-Oct-19) but agreement from 01-Dec-2018 to 31-Oct-2019 (i.e. 11 month rental agreement) signed on 01-Oct-19 but valid from 01-Dec-2018 to 31-Oct-2019? Thanks in Advance. Amit