Harassment by Standard Bank

I've just received a call from an agent from a company called MDD saying that they were calling on behalf of Standard Bank. Firstly she didn't have my direct number, she called the company switchboard where they were then transferred to me.

This woman called Mpho then comes on the line and immediately asks me to confirm my date of birth. I'm not in the habit of giving out my personal details to strangers, secondly I do not have any credit card with Standard Bank which she claimed I had.

Even if in collections she can't be harassing people who have clearly stated that they are not the person she is looking for. She then said to me that she will continue calling my company until she gets hold of me. Please kindly resolve this mess. I'm not going to be subjected to abuse by a company I have no relationship with. If this is how your collections deals with clients, it's disturbing and they are doing your brand a disservice. Epic brand fail.