Regarding vehicle sold but still on my name

HELLO SIR, I have sold my activa in 2014 whose engine asking for repair so I sold it to my known mechanic in good faith of rs 10000 as he told me that he would repair it's engine and sold it and also transferred to the name of that person , I have no proof regarding sale and last month I check it online that it's still standing on my name and I called him and he clearly denied that he didn't buy activa from you and saying that you are telling lie, I requested him plz don't do that, remember to whom you sold it, but he is corporate me, so I filed a application to the RTO as well as SP office via registered A.D. now I got a call from my area chowki and police ask me that what you want now , where are you from last 7 years ?. I said him that I admit that it was my fault but now what to do? But he didn't listing, I am saying to him that I want that from now the whole responsibility of that vehicle the person who have it, but he is not ready to listen me , he calls me and ask me to come chowki where I have spent 2 or 3 hour , I am in depression from last two days. plz help me