Nedbank undertaking of responding worth nothing!

I am a business client of Nedbank. On Thursday, at about 15h20, I wanted to make a payment, only to found that Nedbank discloses that my account has been "frozen"! I have not received any prior communication from Nedbank Rustenburg's business division on any such pending action. The account has funds in it. I could not get hold of the allocated business banker nor his senior. Later got hold of another employee, who told me she has just received 5 similar calls of people complaining that their accounts were frozen. She promised to revert back to me within 5 to 10 minutes. Needless to say, I am still waiting for her call and my account is still frozen. I have finally lost the little confidence that I still had in Nedbank! Although I asked in the past that another banker be allocated to me, it was not done! I have three children, for whom I have also opened accounts at Nedbank. Two will complete professional studies this year. I will also advise them to look for another bank!