Pemex Energy - Pemexenergy.com — HDFC bank issue

My name is Rohan. I am using HDFC credit card from past 8 months. I had purchased a product from Amazon(merchant) in the month of february and then after I called HDFC representative to convert it in to 6 month smart EMI. After a day, I received the product. Since I was unsatisfied with the product I returned the product and called HDFC representative again to cancel the EMI. The representative said that the EMI will be cancelled once the entire amount is returned from Amazon (merchant). A day after that the amount was refunded. Even after receiving the refund, HDFC had not cancelled the EMI that I had requested for. In february month statement, they had included the EMI and since I did not go through the statement, I paid that amount. When I checked march month statement, I realized that the EMI was not cancelled. I called their representative again to inform the same. Now, they tell me that only interest amount that I have paid so far for this product will be waived off where in the EMI that I have paid for the month of February will not be refunded. Apart from that I need to pay the unbilled amount for that product. The product was of Rs.3066/- and the entire amount has been refunded to HDFC by Amazon. HDFC are fraudsters. Everyday I make 5-6 calls to their support center for resolution on this issue. They always end up the call saying will get back to you in 7 working days. Its been more than a month now. Still no resolution. HDFC just loot their own customers.