Sim Card **********ly Transferred

I had a prepaid sim card which was used for business purposes and rica was on my name. There was a sim swap done **********ly where my soon to be ex wife changed ownership to her name without my permission. When I went to vodacom at Westood Mall, they refused to assist me saying that I am not the owner. How can Vodacom transfer the sim from my name to someone else without my permission and they cannot transfer it from someone else to my name.