Loan Closure delay n Paying Credit to my account

I am disappointed as a client on this big institution, how can they be unable to credit R42 that I have overpaid my loan account n close the account, I I called on the 6th February 2020 requesting for my account to be closed still today the account has not been closed its Seven days later, I am still being told that the finance department has not paid the amount to my account, but if I was the one that was owing them, they would have already added interest on the account, this Companies rob us and hide behind something silly like Finance department, like the finance department that they are a talking about is in the moon.