Online banking

Been trying for the last 3 days to get an overdraft on my account but your online banking app does not allow me to do so. What is the use of online banking if you cannot get in. Been trying to call your call centre but nobody picks up. I left my number for a return call but no one calls you. I have been with Standard bank for over 20 years but have not received such appalling service of late. Let me know if you still want my business or should I go to Capitec? I believe they the bank to go to. Very disappointed.