Billing me ridiculously

I received my statement on the 9th of March for my last payment to be made to Bruma finance. The payment stated that I owe R158 which is my last payment to be made to them. I made the payment on the 29th of May. Now they keep on sending a different statement and different amount that is outstanding. I don't owe this people anymore but now it seems they are trying to dry me out. I settled my debt and all they are saying is someone will get back to me but nobody does. I want my account rectified and details removed from their system. I now regret ever taking a loan with them.