I had a similar experience with ICICI. In my case it was not even a representative who fouled up; ICICI itself went and misplaced an entire year's worth of post-dated cheques I'd given to repay a home loan.
One day I started getting phone calls from someone at the bank (or most probably a call centre). The calls kept coming even when I was out of Bombay, and this was in an era when roaming rates were high. I mentioned this, but to no avail. The woman told me I'd need to pay a penalty for missing a month. After a month, she helpfully informed me that I had missed
two months.
I was working with the Economic Times in Mumbai at the time, and I escalated the matter to business journalist and consumer activist Sucheta Dalal via the
Consumer Voice India group on Yahoo. I suggest you post your complaint there and see if you get any suggestions.
In my case, things went well. A few days after I published my grievance in the consumer forum, ICICI's deputy MD Ms Chanda Kochhar personally called me up to apologise for the "oversight", and said she was deputing two senior officials (Mr Madhvendra Das and Ms Satinder Kaur) to visit me and set things right. I have to give them credit: they kept their word.
And so, what I couldn't get done even after months of arguing with ICICI's representatives was accomplished in under two weeks. The costs I had to bear for no fault of mine was reimbursed at actuals, and ICICI paid the stop-payment charges on the cheques that they misplaced. After this was done, and they gave me the acknowledgement, I issued a fresh set of cheques as per their request.
The moral: if you feel you have a strong case, it helps to escalate the topic to the top brass, and not waste time parleying with clueless call center employees or collection agents. The latter can only make life miserable for you and give you high BP.