Dishonest, cheating Company

This disgusting company changes it's terms and conditions without informing clients. When I claimed for something that happened in November, they said their T&C's had changed on 1 November. When I asked them why they didn't inform me about it, they said they did inform me. I asked them to prove when the change was emailed to me. She promised to call back and never did. I asked my broker about it and they told me they also received NO notification about the change. That is why they put through my claim as they had not knowledge that it is no longer covered. So how can an insurance company change it's terms and conditions without informing he clients? Only a dishonest, disgusting, lying, cheating and deceiving company will do such as thing. So is Discovery now classified as dishonest?