Who gave you permission to access my information?

I am so irritated by these constant calls - during work hours! I have never given RCS my details and would like to know who did, because I have no clue as to why they think I want a loan or the use of their services. I filed a complaint on their website, but received no reply. I have also told their telemarketers (or consultants - does it matter?) that I am not interested. I want written confirmation that I will not receive post, calls, emails or any correspondence from them. I don't want anything - if I did, I would've contacted them. This is the poorest marketing strategy, as I'm not sure there is a person who enjoys these calls.