Standard bank OTP internet banking

I phoned Standard bank internet banking help line to assist me to change my OTP to be sent to my email address instead of to my cellphone number because there was a mix up with my cellphone provider - instead of changing it to “pay as you go”, they switched off my number totally. I am currently in NZ so I cannot go to a branch. So I phoned the internet banking help line to ask them to change it so that my OTP be sent to my email address instead of to my cellphone number and was told they cannot assist me, and gave me a email address to mail and request this. So then I email the information help line asking the same question and they told me that I need to phone the internet help line and they will change it for me so that my OTP be sent to my email address instead of my cellphone number. I feel like I am just being passed on from one person to another and nobody is willing to assist me. It costs as fortune for me to phone standard bank in SA, from NZ so I cannot afford to keep phoning them and getting no help. I am absolutely disgusted with the servive that I am receiving from Standard bank.