Capitec just wants people to in debt for the longest time.

So i took out a loan with Capitec and i was advised to pay extra when ever i had extra money, which would help me settle my account sooner and reduce interest but to my surprise i had a balance of R12 032.98 on loan and i paid R10 500 and i still have a balance of R1950.30, were as my installment is R1529,30 now my question is what happened to adding extra money on your loan to reduce my interest on loan? off the balance R1950.30 my settlement fee is R2347.95, capitec just wants their clients to pay them back for the longest time.