R3K interest on R13K balance is too much !

I wanted to settle my loan earlier this month , I didn’t have the full amount but I paid enough to make sure that what’s left is almost close to the instalment amount . I paid R130K on a balance of R143k . Meaning I’m left with R13k to close off the account . Capitec charged me interest of R3000 on a balance of R13K which is too much as I have reduced the debt quite substantially. This interest is equivalent to what they used to charge me before I made R140K payment . That cannot be legal , the interest is too much ! I’ve had another loan a revolving facility where they did the same thing . I want my money back ! Enough with ****ming people capitec !