Lack of customer service action

Approached Nedbank( Canal Walk) a while back regarding a "service provider" who has been harassing me non stop regarding an outstanding amount of money that is "owed on a Home Loan". What is strange, is that I never had a Home Loan with Nedbank. I spoke with a consultant by the name of Chad who took down all the information as he would attend to the matter. Received one call back indicating that they were still "investigating". A few weeks passed, still nothing, and eventually managed to get hold of the Branch Manager who promised to also investigate, and lo and behold...heard absolutely nothing. When ones' query equates to close to half a million Rand's that is allegedly owed, then surely this type of query should be expedited to be resolved as fastidious as possible. The company in question supposedly collecting the debt on behalf of Nedbank is Sustainable Collection Solutions. Let's see how long it takes to get a response after submitting this post.