Big Corporate cannot even change debit order details

I emailed change of bank details 29/06. I then got message to call, which I have done on 04/07 Spoke to Sihle at 18h02. Got confirmation bank details were changed. Next day logged into the website and notice bank still not changed, sent another email, days later get email back please contact 135. Really!!!!!! How pathetic you do not do your job, you confirm a job is done but not done, then have the nerve to tell me to call you. But I promise you if the deduction is not going through minutes later I would be called. You have my instruction, you have my call to change and was verified. Do your job and send me an apology from each of these *********** people who handled this matter. Make sure that debit order is changed before even trying to attempt contact with me.