Manipulated by debt collectors

I have dealing with this debt collectors for more than 2 to 3 years now. I was owing a foshni acc, then thy called nd make arrangements for debt order, fine. The debt order when throgh for the period of 1year same couple months. Whn I asked their statement I was shock to find out that the balance on a statement were still the same. I reliased they are charges like SMS, phone call, statement sent nd receiving cost, receipting fee for settlement payments nd so on. I called foshni nd requested balance on my acc , thy told nd I wrote it down nd the agent fee of plus minus R1000. I hve continued to pay the acc until to the last installment( April 2018). During our first conversation I was told tht all the interest nd cost are included nd no extra cost added. Since thn I hve stoped to pay tht acc till today. I requested a recording of our conversation thy refused with it. Until today my acc is not resolved.

Please help me resolved my acc because am blacklisted.