Why do the companies we give our business to not listen to what we want and don't want!

I am a client of Discovery Health, I never gave my permission to be contacted by Discovery for sales calls, yet I have received 2 sales calls this week. When I ask the sales lady if i can speak to her team leader who apparently gave her my number for her to call me, the call conveniently drops.

I don't phone and bug the people at Discovery Health and waist their time telling them about my company products so why are they phoning me wasting my time with their company products twice in one week when I made it perfectly clear the first time they called me in the week that I was not interested as well as all the times they have called me before this week.

Maybe if they followed their clients instructions they might a) have more clients and b) have lower telephone bills which might result in their clients having to pay lower monthly premiums!