Loan repayment hidden costs

I have a loan with capitec that I have been paying for the past 2 years . I have been using the app to track the balance . Today I wanted to pay it off via the app, so I first checked the balance on the app . My "outstanding balance" was reflected as "R31 965.22". I then used the app "tranfer money" option to pay the outstanding balance from my savings account . After the payment , to my surprise, instead of having outstanding balance as "0.00", instead an amount of "R389.88" is now showing . I then requested a statement of my loan via the app . According to the statement this amount was added as a "discharge int ". This then means this was a hidden costs that was not reflected as part of my "outstanding balance" .. and now I an supposed to pay this amout????? It means my loan is not paid off even though I paid the reflected "outstanding balance" amount. Just maybe add this

Please note that I will not be paying any extra money to the account as according to my knowledge I paid all the amount that was outstanding as was reflecting on the app. Please kindly send me a paid up letter confirming closure of the account as I want this settled.