Very poor service from Standard bank

Yesterday I called the Standard bank prestige bank team to change the number i receive the OTP on. I was told I can only do this change physically at the branch. I went to the Noordwyk branch where I was assisted by a very rude lady called Hlengiwe. She said the number would be changed within few hours, it is 24 hours later and number hasn't been changed. I called prestige banking this morning and they are not able to help. I must not send an email to get someone to look it. I am now being sent from pillar to post just to get a cellphone number changed. This is very disappointing and frustrating.