In general there is no separate capital amount and an interest amount, there is one continuous balance that goes up with addition of interest every month and down with the payment of a repayment. So trying to break it down into the two parts would mean going through every month to see the interest content of that payment and the balance would be what the capital would reduce by that month.
Have you looked at annual statements to see the flow of transactions so you can see if or where the balance was increasing?