This company does not want to stop harrasing me!!!!

This company does not want to stop harrasing me dailly. I have told them numerous times that I am not interested in their free girts and cover and that they must stop calling me. They call me 3 to 5 times a day, if I block the one number, they just immediately call from another number and another number. And then they do the same on my work phone immediately afterwards. I am getting into trouble at work, cause my phone keeps ringing. How do I get this harassment to stop. This is the absolute worse company!!!!