Prosperitas Not responding

Last Year I pulled my own Transunion Report just to see that I was handed over for non payments.<br> After emailing Prosperitas they informed me that I was handed over for bad debt for not paying school fees, that after my ex wife made arrangements with them. I paid the outstanding money within 24 hours.<br> I requested that they send me a letter stating that everything is paid up. Ever since September 2014 I have had no response from them at all, All I need is a letter what is so hard about that?