Unable to make necessary payments

For several days I have had problems making internet payments. The OTP is not being received by my phone in time. A series of OTPs will come through hours later - all to no avail. I have been unable to speak to anyone at the call centre. Instead I hear long recorded explanations which end in an insistence that I register for telephone banking. On the Standard Bank website there is an option for emailing the bank, which goes nowhere (no email address is given).