Consumer Redressal

Dear Sir, I hv puchased a product ONLINE through Indiatimes shopping in EMI thourgh HDFC BANK CRDIT CARDS. But the order has been cancelled by the site because the product was not available at them. they refunded the amount in my credit card but the HDFC BANK CREDIT CARD team has charged me with a interest of rs 357.00 for that transaction. But sir since i haven\'t cancelled the transaction , it has been cancelled by the merchant then how can hdfc bank charge me with this kind of charges . please provide me a solution and also there representatives provides me wrong details and suggetions , it feels they dont know about there job properly . I have all the recording when i have talked with there representatives and how they misleaded me. So sir please provide me solution.