Mickey Mouse Collections Agency on EDC Panel

My FNB loan account was handed over to Ismail and Dahya Attorneys At Law with an arrears amount of R703 which I have paid to the bank. I am still within my loan term and paying my monthly installments but this stupid agency "Ismail and Dahya Attorneys At Law" is contacting me for my full outstanding balance. The bank has advised that my account is up to date but how do I get these fools to stop contacting me?