MBD harassing me without cause

Last week this company SMS me asking that I pay my ABSA credit. (my wife and I have never had an ABSA account ever in our lives. I called them asking what this was about. Apparently someone with the same surname, not first name, and born in 1951, I was born many years later. I explained to them that I did not know this person and please sort it out. Within 24 hours I was bombarded with pre-recorded messages saying if I paid I would receive a discount. Then they started asking me to tv account. Apparently, I am now MS instead of MR, I have blocked their number so many times and they just use new ones, and call me early in the morning, when I answer "Good morning Ken speaking" They're silent and then hang up, obviously expecting a ms A Atkinson.