ICICIcredit Card — Worst customer care service

Address:

Chennai, Tamil Nadu

Card no.[protected],
Last two months i am paying some of amount as interest. As i didnt purchased according to my knowledge, without that they mentioned some charges as interest in the last two months. I made one payment as mentioned, but the same thing happend this month statement also. When i called to customer care, they didnt giving me proper response to me, one of the customer care staff spoke very irresponsible, when i said give me a valuable reply or else i will raise a complaint againt you. He simply said, do whatever you want we are not responsible for this problem. I made so many calls but no use of that simply transfer the call to some person and that person put me in hold for 45minutes, at last call got disconnected. This incident made me too much stress and impatient. I need to know the truth behind this confusion made by this icici credit card department
When i not purchased anything why should i have to pay that interest charges ?
Second thing why this people not helping to solve the problem in customer cares.!

Regards
Saravana kumar