Ask Afrika

I received a call while sleeping from a call agent working for Ask Afrika. Then get bombarded with survey questions. The manner in which I was addressed was a very unprofessional way. The name of the lady is Nella Israela. The lady spoke to me as if I was her friend. Very casually. I really did not appreciate that. Long story short, wr ended the call in not a very good manner. She ended up sending me threatening messages on my private number on what's app and make reference to my mother and father. It cannot be allowed that clients be treated this way. I would like to know how I can proceed with this matter for it cannot be left undealt with.