SIM swap done without my permission

A SIM swap was done on my CellC SIM card without my permission a week ago.<br> <br> 2 months ago a SIM swap was also attempted but I managed to cancel it before it could go through. This time however I wasn't as lucky. Surely there should be more stringent measures in place to prevent these ********** SIM swaps from happening?<br> <br> Please reverse the SIM swap that was done on my number as I urgently need ownership of my number.