Cell phone: Beware of SIM card swap fraud. From University of Stellenbosch. Information Technology

... A SIM card swap fraud occurs when criminals obtain and utilise a replacement SIM card to acquire security messages and one-time passwords (OTP) sent to you by the bank. Using the OTP, criminals are able to change, add beneficiaries and transfer money out of your account using your personal information that they would have obtained through phishing. 

How does a SIM swap scam work?

What should I do if I suspect an unlawful SIM swap?

What should I do if I suspect an unlawful SIM swap?

Link to full article