Very poor service

I took out a loan with Capitec and have been diligently paying my monthly installments, even making extra payments to reduce the balance. However, instead of my loan decreasing as expected, the amount keeps increasing. I’ve contacted Capitec multiple times, but no one can provide a clear explanation. I keep getting transferred between departments with no resolution. How does paying more result in a higher loan balance? This is completely unacceptable and extremely frustrating. Poor service and lack of transparency