Axis Bank — regarding credit card payment

Address:

New Delhi, Delhi

I am holding a axis bank credit card, in the month of September I purchased my personal goods worth 22305, against this transaction I recieved a call from bank customer service centre to convert my transaction into 6 months e.m.i and i agreed for same. But when i had opened my a/c with the bank i had given them auto debit command to pay all my credit card payments, My above transaction is paid through automatic debit command from my a/c in one shot., But till today the bank is levying interest on my e.m.i for the above amount which is wrong on my part, i had contacted them and personally visited the branch but they are not helping me regarding my issue, they had told me that the charges cant be revert back once they charge. You are kindly requested to plz help me in my issue and get my money back which i had paid in advance for the above transaction