Repeatedly being harassed

In spite of the fact that I already have business with Standard Bank, they choose to repeatedly phone my telephone number looking for a "Stefan Kruger". Over the last 2 weeks, I have had 3 phone calls. In spite of my attempts, friendly initially, to make it clear that I am not the person they are looking for, they still insist phoning me. Do they value their customers so very little, that they don't even bother confirming they they may be calling one of there actual customers? The make empty promises every time that they would escalate and apologise, but actions speak louder. If it continues, the only option may be to take my business elsewhere and simply block SBSA from contacting me in future. Maybe the simpler in "simpler, better, faster" refers to their systems... Whether or not it is SBSA direct or their partners, the same applies. How little do you value your customers?