FNB most disgusting bank all ****s

After having made payment arrangements with FNB and made my monthly agreed payment I just received a call from a woman from some company called NBD screaming and threatening me that if I don't naje arrangements directly with them they keep calling and harassing me. So now FNB think they the mafia. Someone from FNB batter call me back as I will stop all payment to them if this is the kind of behaviour and bulling they going to use.