Ridiculous Premium Increase

I moved my insurance over to Discovery Insure coming up for a year ago. I have must received my annual renewal notice and my premium is increasing by over 25% - this despite no claims in the year and no changes on the policy. I have requested explanations and have received a stream of emails that sprout forth theoretical blurbs and the rest but absolutely no facts to justify a 25% increase in my premium! I cannot believe that a company like Discovery can just send so much meaningless ******* out to try and justify this increase. Could it be that they drop their rates to catch you as a client and then at the first opportunity smack their rates up? Whatever the reason it is not acceptable - I will be looking to move my insurance for sure.