[Resolved]  Bajaj Finserv Lending — charging interest on emi

i bought a A.c. on dec 2008 from a shop and in kolkata and choose bajaj finace for loan, rhe emi was set for 8 mnths @ rs.1667/month for 8 mnths, i have paid all my emi in august 2009.my salary goes directly to the bank as i'm a government employee.all the emi deduction have been done by the bank. now the problem is that is in January 2008 they didn't deducted the emi amount but on 16 February 2009 a agent of bajaj finserv lending came and collectd the emi amount in cash and gave me a recipit for it with all the details.the rest of the 7 emi's were allm paid by the bank.now after 4 years they are sayin that u haven't paid your january emi and we will also charge interest on it. but i hav paid all my emi's and have got prove of the recipit that the agent gave me and also all the emi deduction form my account in myb pass book... can they really charge any interset because i hav paid all my emi's.