Not interested!!!

Who do I have to speak to for home choice to stop calling and harassing me? I receive at least 3 calls daily and on every single call I have asked the sales agents to stop calling me as I am not interested in purchasing anything from Homechoice. I have no idea where they received my contact details and was advised they they cannot remove my details from their system, nor is there a complaints process. Please stop calling me. I am not interested!!!