Unhappy

I was informed by the consultant at the bank that inorder to reduce my loan amount and term I can use the option of ad hoc payment which I did and it reduced my loan amount and I have proof thereoff as I printed out the statement,so month end arrived and then month end they also deducted my normal agreed upon installment but to my suprise instead of the loan amount going down it went up after the payment.and I have proof of tht too coz I saved the statement.please rectify this immediately and adjust the loan amount correctly as this is totally unacceptable.