Corporate Society Bank loan repayment notice after 20 years

Recently we got a notice from the Adilabad district corporate society bank stating that as per Telangana coperative society Act under section 71 of 1964 mentioning that we had to pay the loan amount of 1,50,000. The issue is my grandparent took the loan from the society bank in the year 2000 and after that they used to pay installments year by year and once when y s rajashekar reddy was CM he had given loan waiver to such loans but as per the bank team told me that even after that waiver we had some remaining intsallment to repay which summed upto 22,923 and that is on 2014. We never know about this loan untill we get a notice from bank in which they mentioned that we need to pay 1,50,000 with the interest calculated at 15%. Ater 1 month they again sent the notice by reducing it to 80,000. We don't have any idea about the loan because all this matters were handled by my father and he had died in an accident in the year 2012 and we have no idea on this loan until we receive this notice. So, when I searched about all this I came to know about the limitation act of 1963 where it was mentioned that if bank never asks you to pay loan within 3 years with proper notice then it will have no right to file a case in court. Is that true? How we should proceed further ?