Capitec with Brooks & Luyt

Hi my name is Sam. I had two loans with Capitec bank and after falling into financial difficulty found it hard to repay my loans. Capitec handed my loans over to Brooks & Luyt and I found that although I made payments on my loan amount, the interest of 26% per month is so high that my balance is increasing rather then decreasing. I phoned Capitec who informed me the interest is determined by the collection company and the collection company whom i did not get into agreement for a loan nevermind the high interest rate. Is this right because i really want to pay off my debt? by now I already paid back more than the original loan amount to Capitec.