FULL OF ****

I had 1 month arrears and I paid R15200 in December my arrears amount and my December installment my balance was R327000 and after the payment the amount didn't decrease to show there was a payment made, I called and the guy who doesn't know his job told me nonsense, the installment of R7639 for a 2019 car include interest and capital, now this January I paid again R7639 the balance went to R319000 and i was happy because my installment decrease the balance. now when i check the balance is R324000 has gone up again WHAT THE HELL IS THIS I NEED ONE OF THE MANAGERS TO CALL ME REGARDING THIS AM SICK AND TIRED OF THIS BANK FULL OF ****