Banking details changed

I have recently changed bank accounts from Standard bank to Nedbank. I asked the bank to please move my debit order from Standard bank to Nedbank. I received a email to say that is has been done. I went into a Cell C branch to just confirm and when I went there they had no idea how to check and said I should call in. I called in on the 03/06 and spoke to Thabiso around 16:30. I asked him to please send me proof that is has been changed as I don't want my debit order to bounce as I already closed my old account and only have my new account. He's responses is literally of no help. I am doing everything I can on my side to ensure you guys can debit the right account but it is impossible fpr your staff to assist. Can someone please call me to sort this out.