Borrowed 20k loan from a person

Dear Sir/Madam, As am mentioned in the above subject my father had borrowed a 20,000 from a local person on march 2016 and he had signed on the E stamp paper agreeing to give interest also with witnesses and 1 of the witness is my uncle. I don't know whether he signed on the same day or not. And more over my uncle also some 1lakh from the same guy and he couldn't repay it. My father on june 5th 2018 he expired due to cancer but he didn't say anything about paying amount to that guy. But for the other guy he said and we paid them more over ma father had wrote it in a dairy. We believe that my father paid his money but in good faith he aware of tearing e-stamp paper. After ma dad passed away he didn't say anything from past few months if i go to my native ma uncle will inform to that guy and ge will come to my home and ask for the money. I don't know whether that guy has the licence and he is such a guy give money to farmer and he won't even leave 1 month interest. How can he leave for 3 years? Witnesses have signed on the top of the matter is that valid. Please help me out in this. Thanking you,