MFC taking me for a ride.

I bought a car in 2007 and the car was financed by MFC , I have been paying since 2007 till today 2018, the debt is not decreasing, the principal debt was R103 759, MFC says I am owing the R100 000 while i am paying R2500 every month. I am failing to understand why the debt does not decrease. I cant even get the explaination. I feel like MFC is taking me for a ride. How can i pay R2500 every month for over 10 years and only to find i am still owing R100 000? It does not make sense. I will never allow to be financed by MFC or advice any one to be financed by MFC considering what the MFC put me through.