Bajaj Finserv — Unauthorised cheque bounce and late payment charges

I had purchased an led for which i had a loan taken through vijay sales. I had emis running which were directly debited from my hdfc salary account. I changed my job in fabruary 2016 and so wrote an email to bajaj finserv to organise change of my account. I also called their customer care and no response. Even after that, i did continue to pay the emis through hdfc since there was no action taken to change my ecs.
I then stopped since the hdfc account got converted to regular account. They had their recovery agents call and take in cash, and during that time too i submitted the ecs form and cancelled cheque of the new account twice and nothing was done. I even went to the goregaon office to get this sorted but nobody even met.
Now i have last emi left and i have been telling their recovery guys to first set off the late payment and bounce charges, give me a clearance letter, get my card activated again, and i will pay the last emi... Still no update from their side.
My cibil score is unnecessarily getting spoilt because of their fault. Request someone from bajaj finserv to please address to this immediately.