Stop harassing me with phone calls

"Insanity is doing the same thing over and over again, expecting different results."

This is the definition of the Neotel call center. I have now repeatedly said to them that I don't know anyone called Christiaan Nel and yet they keep calling me, asking for this person. My answer is not going to change, it's not my problem if your client used the wrong number. These calls need to STOP!!!!