Intimidating telesales staff

Outsurance has called me numerous times throughout the days and they do not seem to understand that I'm not interested. Today was the last straw, somebody actually phoned me today and tried to intimidate me and raised his voice at me because I did not want to take Outsurance and asked why did I hang up on him earlier and being very aggressive with me. If your call centre has such horrible angry staff with no professionalism whatsoever, then I will probably have to take insurance against YOU. Such a horrible company and staff and scary experience.