HDB Financial Services — Useless charges by HDB Bank

We have a personal loan from HDB loan. It's about to end in June. Lately they have started levying charges on our account. For the month of January we weren't able to keep sufficient balance in our account but we did the emi payment online on time. Still they levied a charge of around Rs. 884 and in addition the bank levied charges of Rs. 590. When we went to resolve this issue in HDB branch, the manager told us that our payment was on time and the charges of Rs. 884 will be waived off once the loan will be completed. But now few days later HDB tried to debit that account from our bank account and an additional charges of Rs. 590 have been levied against insufficient balance. This is such a pathetic service both by HDB and Canara Bank. We haven't expected to be cheated like this by HDB.