HDFC Bank — Rtn charges

Address:

Kolkata

I have hdfc sal account and get personal loan and two Wheeler loan from hdfc bank i paid every month emi 3744 for personal loan and 5637 for two Wheeler loan. but once i coudn't maintains balance in account and that time i was charged with overdue charge which is around 236 Now, after four month they charge me 236 rs for emi rtn charges. If i have already paid overdue charges then why hdfc is again charging with emi rtn charges.