Sim swap done while I was using my phone

Very risky. They did a sim swap on my number while I was using it for a ********. Very very risky they cant even check if a number is working but allow ****** to do a sim swap. Then you as the rightful owner will struggle to cancel that sim swap and get your number back. I have a very concerning question, Does it mean that they are not able to see if one is using the number but block you and give your number to ******????????