my refference number was wrong entered

Dear:I deposited money into my service provider which is nashua on the 3 december 2014,then the teller made a mistake with a reference number so now the provider has put me in arrears, when I went to nedbank to fix it they said they will fix it within 5 days n call me but they did not fix it or call me back, on the 27 february I went I again this two people who said will call me back once its fixed by 2pm but never called me back! And the service provider has taken me to lawyers now due to their mistake they not willing to fix