Owner sell vehicle which was on loan and refused for RC transfer

I purchased a 2nd hand two wheeler. During purchase I was not aware it's on EMI. I paid the amount and agreement were signed . The owner always made excuse whnever I asked him for RC transfer. Almost 1 year passed he is always making excuse. Then I went to RTO, then I came to know that vehicle is on loan and needs NOC from bank. Now I contacted again the owner and at present the owner of vehicle has died . I contacted his family mamber but their response is negative . Please advice me what should I do. The vehicle is my liability or the owners NOK. Who will pay the remaining EMI? I have the original RC and original notary aggrement. They are showing negative response so Can I file a case against his family to pay remaining EMI and give me NOC Plz advice.