My friend's father saved his contact in the phone as "Sin Huin" and leaked his number to scammers

My friend's father hates him because as a child he chose to live with his mother, which forced the father to pay alimony. So he registered his son as "Son of a Jerk" and started giving his number to scammers who constantly call him. Now the scammers are driving the son crazy, and he has explained a hundred times that he has nothing to do with it, but they don't care. What should be done in such a situation???