Poorest service ever!

I phoned RCS after getting retrenched last year December 2015 and I asked them on three different occasions how much I still had outstanding on my loan I took out for R15000 in 2013, they gave me the same amount on three different occasions and I did an EFT that same day. But for the last two months now they keep on telling me I still owe them money even after I phoned them and the man told me he would sort it out I owe them nothing it was a mistake o they're side after I HAD TO HOLD 20MIN just to reach some one. And now this month again I do not have the money to keep phoning them why can`t they just sort this out. It took me just as long to have my card account with them restructured, almost 3months of phoning and explaining and being handed over by mistake. I need serious help with this company!