No email response!

I've been in sending emails to various email addresses of standardbank since September 2021 just to request someone to assist me in changing the contact number for my standardbank APP. I cannot call standardbank because I have been working in Kazakhstan since September 2021. prestige, prestigedirect.northwest, SVC, IBSupport. But to no avail. I've had responses from various prestigebanking consultants all referring me to the IBSupport email. BUT, after a confirmation email and a promise to respond within THREE days, nothing happens! No responding email! No answers! NOTHING! I have various accounts at StandardBank, but are seriously considering closing them and moving to another bank.