[Resolved]  HDFC Bank Credit Cards — Late fee charges

Dear Sir,
I was using HDFC credit cards and had been paying all dues in time. It was the statement of Oct 2007 that showed a late fee of 400/- and on e mailing customer care, they reverted the late fee. Astonishingly, the next statement reflected late fee reversal and another late fee of 400/-. Next began my ordeal of innumerable phone calls and e mails to customer care and all my statements came with cumulative increment of dues though I had stopped using the card.
Now I have been served a DMS letter showing a due of Rs3900/- odd. I had sought clarification and immediately wrote to them, no answer till date. I have been told my account has been de activated and reward points seized but bills are coming with monthly cumulative increases. On contact, they promise me to call back to come to a solution, but no call so far.
My question is if I could pay 54000/- at a time to clear dues, couldn't I pay a late fee of 400/- if it was justified? Who is responsible for this harrassment?