Harassing the wrong person

I've been receiving calls now and then and a bunch of sms's regarding an outstaning amount for SABC, only problem its for a different person. Every time they phone me I tell them that they have the wrong person and that someone used my number or mayde a typo, they just don't care. I've had this number for more than 20 years, but they don't get it. I am not Ms N Ameer.