Unsuccessful Change Of Cellphone number

I went to Absa Irene village mall to change my contact number on my profile. I specifically told the lady that was assisting me to change the number for everything in my Absa account because I am no longer using the old number, she agreed and told me its changed and I received an sms confirming this, now to my surprise when I do online transactions it sends me the verification code to the old number of which I said she must change that. I am so angry because I waited such a long time to be helped and now this, the worst part I can't even change this online I have to go to the bank again, which will be another waiting time and this is inconveniencing me right now as I need to do transactions right now