Bad service

So 2 months ago i was told that my account is in arrears of R79. I paid my installment with the extra R79 now my account is in arrears with R749. I called the branch and Edith said there is nothing they can do. I must call head office. I was told the manager will call me back, it has been a week now. Still waiting. Where is my money going to Lewis? Worst costumer service ever. Stay away!!!