This just happened to a colleague:
"I received a call earlier today about an MTN upgrade. Long story short, the guy wanted me to accept a FNB (my bank) notification which would “authorise the upgrade”. Luckily 1) my TrueCaller app showed two phone call screens; one was “MTN Online Upgrades” and the other was “MTN Scam” and 2) I did not want to give my I.D. number over the phone but the caller seemed to have it already. In fact, he had all my info because I refused to offer the info so he read it to me CORRECTLY!
When I asked the guy to email the info to me so that I could read through it and check everything out beforehand, he told me that it was not possible."