Horrified by MTN ***** department

I had a call today from an unknown number telling me that a certain person has requested a SIM swap on my number. After telling the person that i'll do nothing over the phone they hung up on me.

Here's the scary bit. I called the MTN ***** line and spoke to a Nondumiso Gumbi who told me that I must download the MTN App and end this transaction. I then questioned her why I must do that and she said that they MTN could not do it. I then said what if I or an older person used a phone that couldn't download the MTN app and she said I must go int a MTN branch and they will download the app on their phone with my details and do whatever is required. I then indicated that I was horrified as she has advised me to put my details on someone else's phone in order to sort the issue. What could that person now do with my details and credentials etc....? The thought doesn't bare the thinking about. 1) Why can't the MTN ***** department help me?????? 2) How could a MTN ***** representative advise me to do something like that? 3) Why must I have to download an app from MTN to sort this issue out? 4) Now that I've reported the issue will MTN refund me if any ***** is perpetrated using my number?