improper instalment statements

sir .my name is kamal kishor pathak. there is my credit card from hdfc bank. I have purchased a fridge with the instalment from credit card. before purchasing I called to customer care. there they told me that instalment will automaticaly cut from my salary account and will be equal in every month. now this is not going as they told me. kindly make good currection of this problem . instalment is going very high. THANK YOU