Central Bank Of India — About loan and no due certificate

Sir i had taken loan from central bank of india branch mainpuri u.p. in 2003 but i did not give regular emi because that time i have no job even some emi were given by me after that a notice from the bank i have got in which they tried to settelement for one payment and then i agreed and i gave all payment in 2013.. After 2 or 3 months bank gave no due certificate.. But today on 28/05/2015 a bank reprenstative came in my home and told some amount due for your loan.. Sir pls help me they harres me and insist to pay the due instead of giving me a no due certificate... Plz help i am not in this condition to pay again the loan due... I think you will help me.. My mob no. [protected]