HDFC Bank — one assist cancellation

One assist team deducted rs1299 from my hdfc creditcard without intimation and they converted into emi also. When i given for request for cancellation they are telling to me that we will not able to refund ur total money which is deducted. Eventhough there is no mistake from my side also they r not refunding my total money which they r duducted frm my credit card.