Phone hacking, how does this work? Advice needed!

[Gardenergirl11]

Someone in my family has had their phone hacked and the person has got into their banking app and taken thousands.
The first thing that happened was that they received a pac code, then the mobile network disconnected a day later.
An account on a store credit card was then blocked.
Then thousands were taken from the bank.
The person doesn’t have any recollection of handing any details over or clicking any dodgy links.
I would really like to understand how this can happen, can someone who knows explain? I want to make sure it doesn’t happen again. This happened over the course of a few days so potentially if they acted faster it may not have been so bad. I also want to make sure it doesn’t get any worse.
The bank and phone company are now aware but I am encouraging them to go to the police.

Well they must have given out the code

Do you mean the pac code? I don’t know who they would have given it to but I’ll see if anyone called them to ask them.

Could the PAC code have had spyware attached when opened..I'm just guessing.
So many ways to get diddled now it's sickening.

Sounds like SIM swap fraud

https://www.which.co.uk/news/article/sim-swap-fraud-doubles-year-on-year-how-scammers-steal-your-phone-number-aB0TF1O6hUrv

Thank you. This sounds like exactly what it is. So scary.

Devious AF and scary.. thanks for the info latetotheparty.