The Faces of SPAM?

Today I received my second call from "First Federal Investments" trying to sell me a funeral policy on behalf of FNB. I was a bit suspicious the last time they called, because they aren't listed in the phone book and the First Rand Group have never heard of them. So much for being part of FNB.
This time I asked the caller a few more details, and was then put on to the supervisor, an arrogant cocky man who insisted that they are doing nothing illegal but wasn't able to answer a few basic questions. What he was able to provide me with was the physical address and phone number of the company. After calling them I got their fax number and an email address, which gave me the correct name of the company:

Direct Channel Marketing (Pty) Ltd.
4th Floor, 328 Kent Avenue, Randburg, 2125, South Africa
Telephone: +27 11 293 9200
Facsimile: +27 11 781 1568

I confirmed this with the registration details of their domain name, www.directchannel.co.za, and visited their web site, which makes interesting reading. It would appear to confirm my suspicion that they have absolutely nothing whatsoever to do with FNB, and their marketing script is misleading, and there is no registered financial services provider called "First Federal Investments".
I have written to them and informed them of my desire not to be contacted with marketing calls, and demanded to know where they got my details. I'm entitled to do this in terms of the ECT Act.
As far as I'm concerned, these guys are nothing more than spammers, and they do not have my permission to use my personal details for any purpose whatsoever.

Update: Suleman Shaik confirmed in his email today that he has no idea where my details came from, and referred me to the "Director" of "First Federal Investements", Warren Ebersohn. The fact that they won't/can't tell me where my details came from means that their company is not geared up to be compliant with the ECT Act. Can you trust a company like this? I don't.