ABSA sucks

I am very disappointed in the service I am getting from ABSA after over 10 years of supporting them. They promise to call back but they never do, I spoke to a "supervisor" who promised but never did. I have been paying my bond every month without skipping any payments, I actually pay 8 x more than the installment and still ABSA is loading interest upon interest without a proper explanation of why. If we ask about the Induplim rule they just say they don't know. If a supervisor/manager from ABSA could just call me and rectify this because I don't think this is fair.