Abusive behaviour

Two weeks ago I received a call from Michelle, Outsurance employee. She insisted on giving me a quote and my mistake was to entertain her. Ever since I have been getting calls from different Outsurance employees. In a day I get a minimum of 3 calls. I asked them not to call me again but they refuse to listen and use different numbers so even if I block them they'll still manage to get through. I'm not their customer and I think they should respect me and stop abusing me.