Harassing Wrong Number Calls

I'm not sure if these consultant workers are just in component or just stupid. I've been getting up to 6 calls a day from this annoying company, 3 of the 6 calls get disconnected when I answer and when I finally speak with a consultant, they ask for a Mr. Chauke and this is not me, then they have the audacity to ask me when have I last spoken with him. I bought my number from MTN 6 months ago and these idiots keep on harassing me!!!!