FNB Connect ****, is your money safe?

Somebody app**** for an FNB Connect Sim Card and linked it to my FNB Bank Account.

I called FNB Connect after seeing payments come off my account since December. They said go to a branch

Went to FNB Woodmead, they called FNB Connect. They ask me if Im sure its not mine coz there is a whole call history etc. We called the number and someone random picked up!

The guy says the sim card was picked up at a branch so he cant see which branch and what ID they used to pick it up.

If you're confused, I am talking about a bank here where we keep all our money. How can someone link my account to a sim card, pick it up at a branch with no way to ID them? Is our money safe? Is this an inside job?