No OTP messages

Since August last year I am not receiving OTP SMSs from FNB whenever there's a transaction on my account and now even when I shop on Takealot to pay using my eBucks I am unable to complete the transaction because the OTP does not come through to my phone. I have phoned the call centre, went to the branch and no one is able to help. Many reference numbers but not a single resolution. Utter disgrace and each time I log into my app they want me to upgrade to Private Banking. NO I WILL NOT with this kind of terrible service.