Please help me check the abnomal interest of Bayport Financial Services

I requested a loan at Bayport financial Services in 2013 and I was to pay back to Bayport services an amount of R117 184.00 for 5 years. The agreed instalment was R2450.00 When times goes on I had financial problems and they sent one of their collectors at my work place. We set down with that person and I explain to him that I get it difficult to pay the full instalment and he agreed that they can increase the payment period as I requested to pay R1000.00. I paid that amount but the amount to be repaid was increasing and the money that I was paying was not making any difference as I have a judgment against me for an amount of R175 160.00 on the 17-02-2017 without any notice or documents sent to me. I only saw this Judgement on my report at the National Credit Bureau. I am continuing paying that loan without seeing any progress. They called me to increase the money I am paying with R500.00 to R1500.00 which I did. Please help me know why are they adding so high interest on the amount as the balance of the loan is now R303 499.00. I thought that they will stop on the amount I am owing and hand me over to Lawyers as other companies do. I had other debts that I was handed over with as I explained that I was having a financial problems and I have arranged the payments and they are now paid up. I will be going on retirement and I won't be able to pay this money as it is now three times the money that I owed them. I am still paying R1500.00 every month which I was thinking I will increase as my debts are becoming right. Please help me as when I call they are saying I have increased the payment term but R4000.00 is being added every month. I am not refusing to pay but I feel that I am going to pay for my whole life. Thank you

Annah Ndhlovu