Interest rate escalation

I know i was the one who went to them for help and they assisted me when in need but the interest rate is ridiculous . So after falling ill and had to resign from work i couldn't pay my account which was R10000 when i took it in November 2018 the intrest has escalated my owing amount and they say because of none repayment even though i did submit my documents that i was no longer employed i now owe a balance of R19401 i am so confused of how the intrest is calculated and the consultant failed to explain aswell.