Foreigner Tenant - whose student visa has expired, and agreement also expired not vacating the flat

Hi , Around 1.5 years back I got one agreement done with 2 foreigner students(Africans). The agreement expired 4 months back. Due to their visa not renewed, the rental agreement was not renewed. So I told them to leave the property. One of them , I suppose has left. Another one is still staying. He is not paying for visa to FRRO India. However he got his valid Adhar card and Pancard. He is not able to pay rent also and his deposit is already over due to non-payment of rent. I told him many times in email , SMS and whatapp to leave the property. Here are my questions - 1. Is it required to send a legal notice through Advocate or detailed email notice is also sufficient. 2. I did a e-complaint with maharastra police 2 months back but they are not getting the flat vacated telling it is civil issue. I should go to court. If I go to court then how much time it will for the court to get the flat vacated? Can't police get the flat vacated ? 3. once society did not allowed him to enter based on my complaint - however that person remained outside for full 24 hours then requested me to allow him inside as he did not slept. Fearing if something will happen to him , I allowed him inside. In case something happens to tenants if they can't arrange another property then is the owner responsible ? Due to this fear also I am not putting pressure on society to not allow him inside - once he goes out. Should I fear this consequence - something happening to tenant as he is not able to arrange another property and I not allowing him. 4. Can he get agreement based on Adhar card without having visa ? 5. As he does not have the visa - so can I get help from FRRO to deport him to his country?