ICICI Bank Credit Card — Harassment by bank authorities

I have been holding the ICICI Bank Credit Card since 2006 and has always been partyicular about my payments. In May 2009 I received the Statement for the month of April for an amount of Rs.10391.25. I issued cheque before the due date 15.05.09 and dropped the same in their ATM drop box on 12.05.09 but they have shown the receipt on 14.05.09 and the same was sent for clearance on 17.05.09. Later on due some technical fault (not due to insufficient balance) the cheque got bounced. later on I received a call from their collection agents and i was verbally abused and inexplicable foul languages were used even hough i repeatedly assured that the payment would be made in full after sorting out the issue with my bank. meanwhile they have stopped giving me the credit facility despite having sufficient limit. After being a loyal and active customer of the bank this kind of treatment and verbal abuses has shocked and given me pain and i have been suffering from mental depression due to this incident . please help ...