No one man's calls or returns calls

Why does this bank not answer call or return calls etc.... I recieved an SMS from the bank FNB saying that I qualify for a payment break, in January , however I don't want this as eventually you'd have to pay extra interest on the installment, so I've been trying to call them , I have a private clients account and even have tried to call my bankers for advice for about 2 weeks and no luck it's very frustrating since I'm trying to keep my credit status clear and up to date , seriously considering moving banks to where service actually exist